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Nerve and Nerve Root Biomechanics  

Microsoft Academic Search

\\u000a Together, the relationship between the mechanical response of neural tissues and the related mechanisms of injury provide\\u000a a foundation for defining relevant thresholds for injury. The nerves and nerve roots are biologic structures with specific\\u000a and important functions, and whose response to mechanical loading can have immediate, long-lasting and widespread consequences.\\u000a In particular, when nerves or nerve roots are mechanically

Kristen J. Nicholson; Beth A. Winkelstein


Clinical and Radiological Findings of Nerve Root Herniation after Discectomy of Lumbar Disc Herniation  

PubMed Central

The authors report 2 cases of nerve root herniation after discectomy of a large lumbar disc herniation caused by an unrecognized dural tear. Patients complained of the abrupt onset of radiating pain after lumbar discectomy. Magnetic resonance imaging showed cerebrospinal fluid signal in the disc space and nerve root displacement into the disc space. Symptoms improved after the herniated nerve root was repositioned. Clinical symptoms and suggestive radiologic image findings are important for early diagnosis and treatment.

Bae, Jun Seok; Pee, Yong Hun; Lee, Sang-Ho



Sheaths of the spinal nerve roots  

Microsoft Academic Search

The present study was carried out to investigate the permeability of normal spinal nerve root sheaths around dorsal and ventral roots in the rat. In vivo studies were performed using Evans bluealbumin and lanthanum chloride as tracers. The Evans blue-albumin complex is macromolecular in size and lanthanum ions are small and easily visible in the electron microscope. Both tracers were

C. Å. V. Pettersson



Tractography of lumbar nerve roots: initial results  

Microsoft Academic Search

Objectives  The aims of this preliminary study were to demonstrate the feasibility of in vivo diffusion tensor imaging (DTI) and fibre\\u000a tracking (FT) of the lumbar nerve roots, and to assess potential differences in the DTI parameters of the lumbar nerves between\\u000a healthy volunteers and patients suffering from disc herniation.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Nineteen patients with unilateral sciatica related to posterolateral or foraminal disc

Vincent Balbi; Jean-François Budzik; Alain Duhamel; Anne Bera-Louville; Vianney Le Thuc; Anne Cotten



MRI nerve root enhancement in Krabbe disease  

Microsoft Academic Search

Krabbe disease is characterized by abnormal breakdown and turnover of myelin, leading to extensive demyelination in both the peripheral and central nervous systems. A 7-month-old infant with early-onset Krabbe disease had deceptively normal head images, but spinal MRI demonstrated abnormal gadolinium enhancement of the lumbosacral sacral nerve roots and cauda equina such as that seen in Guillain-Barré syndrome. Abnormal enhancement

Elza Vasconcellos; Michelle Smith



Spinal Cord and Nerve Root Decompression  

Microsoft Academic Search

Tumors of the vertebral column include both primary and metastatic lesions. These tumors can cause significant morbidity consisting\\u000a of lesional pain and pain from deformity. Compression of the spinal cord and spinal nerve roots can also cause radicular pain\\u000a as well as neurologial deterioration including sensory deficits, weakness, paralysis, and\\/or sexual\\/bowel\\/ bladder dysfunction.\\u000a In cases of metastatic lesions, the spine

Keith R. Lodhia; Paul Park; Gregory P. Graziano


Tendon and nerve displacement at the wrist during finger movements  

Microsoft Academic Search

Background. Repetitive motion of the hand has been suggested as a major factor of pathogenesis of cumulative trauma disorders (e.g., carpal tunnel syndrome). The purpose of this study was to investigate the 3D displacement of the median nerve and extrinsic finger flexor tendons (flexor digitorum superficialis; flexor digitorum profundus) as a function of flexion\\/extension of metacarpophalangeal joints of the index

U. Chris Ugbolue; Wei-Hsiu Hsu; Robert J. Goitz; Zong-Ming Li



[Root apex localization of palatally displaced canines].  


Introduction: The aim of this study was to investigate the positions of the root apices of palatally impacted canines with cone beam computed tomography. While it is true that the position of the crown determines the surgical approach and direction of traction, the location of the apex also plays an important role in orthodontic mechanics. Methods: Twenty-seven unilateral palatally impacted canines were evaluated on cone beam images. Measurements were taken using Osirix(®) software, in order to compare the location of the apex of the palatally impacted canine with the apex of the contro-lateral normally erupted canine. Results: The root apex of a palatally impacted canine was usually correctly positioned in the line of the arch. Conclusion: In most cases, the orthodontic management of palatally impacted canines requires little or no root torquing. PMID:22717116

Maire, Claire-Hélène



Median nerve deformation and displacement in the carpal tunnel during finger motion.  


The objective of this study was to evaluate the correlations between deformation and displacement of median nerve and flexor tendons during finger motion in the carpal tunnel for both carpal tunnel syndrome (CTS) patients and healthy controls. Sixty-two wrists of 31 asymptomatic volunteers and fifty-one wrists of 28 idiopathic CTS patients were evaluated by ultrasound. The displacement of the median nerve and the middle finger flexor digitorum superficialis (FDS) tendon, as well as area, perimeter, aspect ratio of a minimum enclosing rectangle, and circularity of the median nerve were measured in finger extension and flexion positions. Deformation indices were defined as the ratios of indices in finger extension and flexion positions. The correlations between displacement and deformation indices were evaluated. There were significant correlations between nerve palmar-dorsal displacement and deformation indices (p?displacement of the nerve (-0.572, p?nerve deformation indices and nerve palmar-dorsal displacement in the carpal tunnel. Since the highest correlations were between palmar-dorsal nerve displacement direction and aspect ratio deformation index, these parameters may be helpful to understand the pathophysiology of CTS. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1876-1880, 2013. PMID:24038546

Yoshii, Yuichi; Ishii, Tomoo; Tung, Wen-Lin; Sakai, Shinsuke; Amadio, Peter C



Intraoperative conjoined lumbosacral nerve roots associated with spondylolisthesis.  


Lumbosacral nerve roots anomalies may produce low back pain. These anomalies are reported to be a cause for failed back surgery. They are usually left undiagnosed, especially in endoscopic discectomy techniques. Any surgery for entrapment disorders, performed on a patient with undiagnosed lumbosacral nerve roots anomaly, may lead to serious neural injuries because of an improper surgical technique or decompression. In this report, we describe our experience with a case of L5-S1 spondylolisthesis and associated congenital lumbosacral nerve root anomalies discovered during the surgical intervention, and the difficulties raised by such a discovery. Careful examination of coronal and axial views obtained through high-quality Magnetic Resonance Imaging may lead to a proper diagnosis of this condition leading to an adequate surgical planning, minimizing the intraoperatory complications. PMID:23412326

Popa, Iulian; Poenaru, Dan V; Oprea, Manuel D; Andrei, Diana



Endoscopic decompression for intraforaminal and extraforaminal nerve root compression  

Microsoft Academic Search

Objective  The purpose of this study was to evaluate the outcome of endoscopic decompression surgery for intraforaminal and extraforaminal\\u000a nerve root compression in the lumbar spine.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The records from seventeen consecutive patients treated with endoscopic posterior decompression without fusion for intaforaminal\\u000a and extraforaminal nerve root compression in the lumbar spine (7 males and 10 females, mean age: 67.9 ± 10.7 years)

Toshio Doi; Katsumi Harimaya; Yoshihiro Matsumoto; Osamu Tono; Kiyoshi Tarukado; Yukihide Iwamoto



Nerve root hypertrophy in chronic inflammatory demyelinating polyneuropathy.  


A patient with chronic inflammatory demyelinating polyneuropathy (CIDP) and central demyelinating disease is described in whom striking nodular filling defects on multiple lumbar-sacral nerve roots, mimicking neurofibromata, were observed at myelography and magnetic resonance imaging. We suggest that these lesions are secondary to recurrent segmental demyelination and remyelination and that the differential diagnosis of this radiological feature should include CIDP. PMID:8114785

De Silva, R N; Willison, H J; Doyle, D; Weir, A I; Hadley, D M; Thomas, A M



Selective nerve root blocks for low back pain and radiculopathy  

Microsoft Academic Search

In the management of patients with low back pain and radiculopathy, selective nerve root blocks (SNRBs) are now a common procedure for both diagnostic and therapeutic purposes. This article reviews the available studies as well as the relevant anatomy, pathology, technical considerations, and complications.

Noor M Gajraj



MR Imaging of Spinal Nerve Roots:Techniques, Enhancement Patterns, and Imaging Findings  

Microsoft Academic Search

The purpose of this report was to review the MR techniques, contrast enhancement patterns, and MR imaging findings for the spinal nerve roots. The phenomenon of contrast enhance- ment of the nerve roots and its relationship to disk disease and failed-back-surgery syndrome are discussed. The MR imaging findings for various inflammatory and neoplastic disorders affecting the spinal nerve roots are

Bassem A. Georgy; Ruth D. Snow; John R. HesSelink


Characterization of a chondroitin sulfate hydrogel for nerve root regeneration  

NASA Astrophysics Data System (ADS)

Brachial plexus injury is a serious medical problem that affects many patients annually, with most cases involving damage to the nerve roots. Therefore, a chondroitin sulfate hydrogel was designed to both serve as a scaffold for regenerating root neurons and deliver neurotrophic signals. Capillary electrophoresis showed that chondroitin sulfate has a dissociation constant in the micromolar range with several common neurotrophins, and this was determined to be approximately tenfold stronger than with heparin. It was also revealed that nerve growth factor exhibits a slightly stronger affinity for hyaluronic acid than for chondroitin sulfate. However, E8 chick dorsal root ganglia cultured in the presence of nerve growth factor revealed that ganglia cultured in chondroitin sulfate scaffolds showed more robust growth than those cultured in control gels of hyaluronic acid. It is hypothesized that, despite the stronger affinity of nerve growth factor for hyaluronic acid, chondroitin sulfate serves as a better scaffold for neurite outgrowth, possibly due to inhibition of growth by hyaluronic acid chains.

Conovaloff, Aaron; Panitch, Alyssa



Ventricular Pneumocephalus with Meningitis after Lumbar Nerve Root Block  

PubMed Central

Lumbar nerve root block is a common modality used in the management of radiculopathy. Its complications are rare and usually minor. Despite its low morbidity, significant acute events can occur. Pneumocephalus is an accumulation of air in the intracranial space. It indicates a violation of the dura or the presence of infection. The object of this report is to describe the case of a patient with intraventricular pneumocephalus and bacterial meningitis after lumbar nerve root block. A 70-year-old female was brought into emergency department with severe headache and vomiting which developed during her sleep. She had received lumbar nerve block for her radiculopathy one day before her presentation. Cranial computed tomography scan revealed a few hypodense lesions in her left lateral ventricle frontal horn and basal cistern indicating ventricular pneumocephalus. Five hours later, she developed sudden hearing loss. Cerebrospinal fluid analysis showed bacterial meningitis, and she was treated with high dose steroid and antibiotics. However, her impaired hearing as a sequela from meningitis was persistent, and she is still in follow-up. Intracranial complications of lumbar nerve root block including meningitis and pneumocephalus can occur and should be considered as high-risk conditions that require prompt intervention.

Ko, Young Sang; Lim, Kyung Soo



Ultrasound-Guided Lumbar Nerve Root (Periradicular) Injections  

Microsoft Academic Search

\\u000a Lumbar periradicular infiltrations (nerve root blocks) are well established in the diagnosis and management of lumbar radiculopathy.\\u000a Lumbar periradicular injections are preferentially performed as fluoroscopically or computed tomography (CT) controlled interventions.\\u000a However, both guidance modalities have significant radiation exposure, at least in part, expensive equipment. As an alternative\\u000a guidance method, ultrasound (US) imaging is also applicable for spinal infiltrations– and

Klaus Galiano; Hannes Gruber


A Unique Case of Intradural Communicating Branches between the Accessory Nerve and the Dorsal Roots of the Cervical Spinal Nerves.  


Objective The accessory nerve has cranial and spinal roots. The cranial roots emerge from the medulla, whereas the spinal roots arise from motor cells within the ventral horn of C1-C7 segments of the spinal cord. Communications have been described between the spinal accessory nerve rootlets and the dorsal rootlets of cervical spinal nerves. In the present case, we report a communication that has not been reported before and discuss the functional anatomy.Materials and Methods During the dissection of the craniovertebral junction of a 67-year-old formalin-fixed adult male cadaver, a connection between the spinal accessory nerve rootlets and the dorsal rootlets of the cervical spinal nerves was observed.Results A communication between the spinal rootlets of the accessory nerve and the dorsal roots of cervical spinal nerves was present on the right and left side. On the right, a communication between the accessory nerve spinal rootlet and the dorsal rootlet of the fourth cervical spinal nerve existed. On the left, there were two branches from the lowest accessory nerve spinal rootlet, one run ventrally and the other dorsally to the spinal rootlet and reached the dorsal root of third cervical spinal nerve. The dorsal root of C1 did not exist on either the right or the left side. Further, an unusual spinal accessory nerve formation was also observed.Discussion This case does not fit into any of the previously described classifications in the literature. Therefore, the different variations concerning the communications between the spinal rootlets of the accessory nerve and the cervical spinal nerves should be kept in mind during both surgical, especially radical neck dissections, and nonsurgical evaluations. PMID:23397124

Seker, A?k?n; Ceylan, Davut; Tatarl?, Necati; Abdullaev, Tuychiboy; Gülbar, Seda; Konya, Deniz; Bayri, Yasar; Kele?, Evren; K?l?ç, Türker; Cavdar, Safiye



Why use steroids in lumbar selective nerve root block ? -A randomized control study  

Microsoft Academic Search

SUMMARY Sixty-nine patients with lumbar pain and lower limb pain who visited our Hospital, were randomly divided into two groups and selective nerve root block (SNRB) was performed: Group S(+) : Received concomitant administration of steroids with local anesthetic at the time of nerve root block; Group S(-) : Received administration of local anesthetic alone at the time of nerve

Yoshinobu Hagihara; Satoshi Ogata; Hirohisa Hirayama; Tadaaki Koyama; Eishi Watanabe



Experimental Studies on Surgical Treatment of Avulsed Spinal Nerve Roots in Brachial Plexus Injury  

Microsoft Academic Search

This review summarises studies aiming at a surgical treatment of spinal nerve root avulsions from the spinal cord in brachial plexus lesions. After dorsal root injury, regrowth of nerve fibres into the spinal cord occurs only in the immature animal. After ventral root avulsion and subsequent implantation into the spinal cord, neuroanatomical and neurophysiological data show that motoneurons are capable




The effectiveness of contralateral C7 nerve root transfer for the repair of avulsed C7 nerve root in total brachial plexus injury: an experimental study in rats.  


The aim of this study was to evaluate the feasibility and effectiveness of transferring the contralateral C7 root to repair avulsed C7 nerve root. Thirty rats were randomized into three groups. In group A, rats underwent whole-root avulsion of the left brachial plexus and contralateral C7 root transfer to the avulsed C7 nerve root. In group B, rats underwent whole-root avulsion and contralateral C7 root transfer to the radial nerve. In group C, rats underwent whole-root avulsion of the left brachial plexus without nerve transfer. Functional outcomes were measured by electrophysiological studies, muscle tetanus contraction force, muscle mass, and histology. Six months postoperatively, increased amplitude and shortened latency of compound muscle action potentials, larger maximum tetanic contractile tension, heavier muscle mass, and larger cross-sectional area of the muscle fibers were observed in the triceps, extensor carpi radialis brevis, and extensor digitorum in groups A and B when compared with group C (p < 0.01). There were no significant differences between group A and B (p > 0.05). Contralateral C7 nerve transfer to repair avulsed C7 nerve root was feasible and effective in this rat model. It should be considered as an option for the treatment of brachial plexus injuries. PMID:23599214

Lin, Haodong; Sheng, Jun; Hou, Chunlin



Intercostal nerves to spinal nerve roots anastomosis (spinal cord bypass) and Harrington rod fusion in traumatic paraplegia — Technical note  

Microsoft Academic Search

Summary This paper describes the technique of anastomosis of intercostal nerves to spinal nerve roots together with Harrington Rod fusion in traumatic paraplegia, with the help of a case history in which this combined procedure has been performed for the first time.

A. Patil



Effects of arterial ischemia and venous congestion on the lumbar nerve root in dogs.  


The development of radiculopathy in patients with lumbar canal stenosis is thought to be closely related to intraradicular edema resulting from compression. However, there is little agreement as to question which is more essential for intermittent claudication: ischemia or congestion. The aim of the present experimental investigation was to examine the effect of ischemia and congestion on the nerve root using dogs. The aorta was clamped as an ischemia model of the nerve root and the inferior vena cava was clamped as a congestion model at the sixth costal level for 30 min using forceps transpleurally. Measurements of blood flow, partial oxygen pressure, and conduction velocity in the nerve root were repeated over a period of 1 h after release of clamping. Finally, we examined the status of intraradicular blood-nerve barrier under fluorescence and transmission electron microscope. Immediately after clamping of the inferior vena cava, the central venous pressure increased by about four times and marked extravasation of protein tracers was induced in the lumbar nerve root. Blood flow, partial oxygen pressure, and conduction velocity of the nerve root were more severely affected by aorta clamp, but this ischemia model did not show any intraradicular edema. The blood-nerve barrier in the nerve root was more easily broken by venous congestion than by arterial ishemia. In conclusion, venous congestion may be an essential factor precipitating circulatory disturbance in compressed nerve roots and inducing neurogenic intermittent claudication. PMID:18536056

Kobayashi, Shigeru; Takeno, Kenichi; Miyazaki, Tsuyoshi; Kubota, Masafumi; Shimada, Seichior; Yayama, Takafumi; Uchida, Kenzo; Normura, Eiki; Mwaka, Erisa; Baba, Hisatoshi



Resection of relevant nerve roots in surgery of spinal neurinomas without persisting neurological deficit  

Microsoft Academic Search

Summary In 42 patients with a spinal neurinoma or neurofibroma, resection of the affected nerve root was necessary in 24 cases for complete removal of the tumour. In 10 of these the resected nerve root was relevant for upper or lower limb function.

R. Schultheiss; G. Gullotta



Stenosis of the nerve root canal caused by disc resorption.  


Stenosis of the nerve root canal caused by isolated resorption of a lumbar disc is a frequently observed pathology, but one about which the orthopaedist still knows relatively little. Henry Crock was the first to reveal its principal pathogenetic factor, disc resorption, and to accurately describe the syndrome and its surgical treatment. A total of 22 patients operated according to Henry Crock's indications and followed-up after 2 years were reviewed. In 20 cases decompression alone was performed, while in 2 cases anterior fusion and MOSS instrumentation were associated. Of the 22 patients submitted to decompression 17 revealed complete regression of pain. Three cases failed: 1 patient had previously been treated with chymopapain, while 3 are awaiting anterior fusion to treat persistent lumbar pain. Follow-up is not sufficient for the two patients submitted to anterior fusion. PMID:1587162

Gallinaro, P; Indemini, E; Tabasso, G; Massazza, G


Connection types between the spinal root of the accessory nerve and the posterior roots of the C2–C6 spinal nerves  

Microsoft Academic Search

Purpose  The aim of this study was to demonstrate the connection types and frequency between the accessory nerve and the posterior\\u000a roots of the C2–C6 cervical nerves.\\u000a \\u000a \\u000a \\u000a Methods  The cranial cervical regions of 49 specimens from 27 human cadavers were used for the present study under an operating microscope.\\u000a \\u000a \\u000a \\u000a Results  Five different connection types between the accessory nerve and the posterior roots of

Canan Y. Saylam; Mustafa Orhan; Z. Asl? Aktan Ikiz; Hülya Uçerler; Mehmet Zileli



Recurrent spinal cord tethering by sacral nerve root following lipomyelomeningocele surgery. Case report.  


A 21-year-old woman had recurrent progressive weakness/hypesthesia and pain in both lower extremities. At the age of 5 and 19 years, she had undergone surgical resection of a lipomyelomeningocele at L5-S1. Surgical exploration revealed that the cord was tethered and pulled over to the side by an excessively short right S-1 nerve root. The contralateral L-5 and S-1 nerve roots were markedly stretched. Division of the right S-1 nerve root resulted in prompt disappearance of pain in the lower extremities and improvement in neurological function. PMID:2045900

Barolat, G; Schaefer, D; Zeme, S



Clinical features of conjoined lumbosacral nerve roots versus lumbar intervertebral disc herniations  

Microsoft Academic Search

Unidentified nerve root anomalies, conjoined nerve root (CNR) being the most common, may account for some failed spinal surgical\\u000a procedures as well as intraoperative neural injury. Previous studies have failed to clinically discern CNR from herniated\\u000a discs and found their surgical outcomes as being inferior. A comparative study of CNR and disc herniations was undertaken.\\u000a Between 2002 and 2008, 16

R. Lotan; A. Al-Rashdi; A. Yee; J. Finkelstein



Nonsurgical treatment for radicular of pain of zygoapophyseal joint cyst origin: Therapeutic selective nerve root block  

Microsoft Academic Search

Slipman CW, Lipetz JS, Herzog RJ, Vresilovic EJ. Nonsurgical treatment for radicular pain of zygoapophyseal joint cyst origin: therapeutic selective nerve root block. Arch Phys Med Rehabil 2000;81:1119-22. We report the first case of zygoapophyseal joint cyst–induced radicular pain successfully treated with therapeutic selective nerve root block. A 56-year-old dentist presented with pain involving the lateral thigh, lateral calf, and

Curtis W. Slipman; Jason S. Lipetz; Richard J. Herzog; Edward J. Vresilovic



Fibrous adhesive entrapment of lumbosacral nerve roots as a cause of sciatica  

Microsoft Academic Search

Study design: Report of seven patients with fibrous adhesive entrapment of lumbosacral nerve roots as a cause of sciatica, whose radiographic findings were negative and who experienced relief from sciatica immediately after the entrapment was released.Objectives: To describe a new clinical entity of fibrous adhesive entrapment of lumbosacral nerve roots with negative radiographic findings.Setting: Orthopaedic department, Japan.Methods: Clinical evaluation and

K Ido; H Urushidani



Nerve root enhancement on spinal MRI in pediatric Guillain-Barré syndrome.  


Guillain-Barré syndrome diagnosis is based on clinical presentation and supportive diagnostic testing. In its early stage, no single, reliable diagnostic test is available. However, a finding of nerve root enhancement on spinal magnetic resonance imaging may be useful. We evaluated the frequency of nerve root enhancement on spinal magnetic resonance imaging in children with Guillain-Barré syndrome. At a single tertiary pediatric center, we conducted a retrospective chart review of children with Guillain-Barré syndrome who had complete spinal or lumbosacral spinal magnetic resonance imaging with gadolinium administration from January 2002-January 2009. Twenty-four consecutive patients were identified. Spinal nerve root enhancement with gadolinium was present in 92% (22/24) of children with Guillain-Barré syndrome on initial spinal magnetic resonance imaging (95% confidence interval, 0.745-0.978). This finding increased to 100% of patients, after two patients underwent repeat spinal magnetic resonance imaging that did reveal nerve root enhancement. Patterns of enhancement were variable, but involved the thoracolumbar nerve roots in all patients. Enhancement of nerve roots with gadolinium on initial spinal magnetic resonance imaging was frequently present in these children with Guillain-Barré syndrome. Spinal magnetic resonance imaging is a sensitive diagnostic test and should be considered an additional diagnostic tool in select cases. PMID:20837305

Mulkey, Sarah B; Glasier, Charles M; El-Nabbout, Bassem; Walters, William D; Ionita, Christian; McCarthy, Michael H; Sharp, Gregory B; Shbarou, Rolla M



The role of graded nerve root compression on axonal damage, neuropeptide changes, and pain-related behaviors.  


Rapid neck motions can load cervical nerve roots and produce persistent pain. This study investigated the cellular basis of radicular pain and mechanical implications of tissue loading rate. A range of peak loads was applied in an in vivo rat model of dorsal root compression, and mechanical allodynia (i.e. pain) was measured. Axonal damage and nociceptive mediators were assessed in the axons and cell bodies of compressed dorsal roots in separate groups of rats at days 1 and 7 after injury. In the day 7 group, damage in the compressed axons, evaluated by decreased heavy chain neurofilament immunoreactivity, was increased for compressions above a load of 34.08 mN, which is similar to the load-threshold for producing persistent pain in that model. Also, the neuropeptide substance P and glial cell line-derived neurotrophic factor and its receptor significantly decreased (p < 0.02) with increasing load in the small nociceptive neurons of the dorsal root ganglion, suggesting that axonal damage may also decrease neurotrophic support in injured nociceptive afferent fibers. In a separate study, roots were compressed at 2mm/s, and held, to develop a quasi-linear viscoelastic model that was validated through comparisons to quasistatic loading. The model demonstrated that nearly 23% less displacement was required to reach the axonal injury load threshold during dynamic loading than for quasistatic rates. Together, these studies demonstrate that nerve root compressions that produce pain symptoms are sufficient to mediate nociceptive cellular changes, and that thresholds for pain and nociceptive pathophysiology may be lower for dynamic loading scenarios. PMID:19085157

Hubbard, Raymond D; Quinn, Kyle P; Martínez, Joan J; Winkelstein, Beth A



Anterograde transport of opioid receptors in rat vagus nerves and dorsal roots of spinal nerves: pharmacology and sensitivity to sodium and guanine nucleotides  

Microsoft Academic Search

We have utilized the technique of in vitro autoradiography to ascertain that opioid receptors are transported in the rat vagus nerve and in the rat dorsal spinal root fibers. In the dorsal roots, opioid receptors accumulated on both sides of the ligatures. In the vagus nerve, a distal accumulation of binding sites was difficult to detect, however, proximal to the

M. A. Zarbin; J. K. Wamsley; M. J. Kuhar



Pathogenesis of sciatic pain: role of herniated nucleus pulposus and deformation of spinal nerve root and dorsal root ganglion  

Microsoft Academic Search

The basic pathophysiologic mechanisms related to disc herniation and sciatica are poorly understood. Recently it was demonstrated that nucleus pulposus from an intervertebral disc could induce structural and functional changes in adjacent nerve roots when applied epidurally, however, it is not known if such changes are painful. In a model for inducing disc herniation in the rat, we found that

Kjell Omarker; Robert R. Myers



Nerve root prolapse into a spinal arachnoid cyst--an unusual cause of radiculopathy.  


Arachnoid cysts are rare lesions of the spine and can present with myelopathy, radiculopathy, local pain or a combination of these symptoms. Nerve root prolapse into an arachnoid cyst causing radiculopathy has not been reported before. We report a nerve root prolapse into a spinal arachnoid cyst presenting clinically as radiculopathy. An 18-year-old female patient presented with mid-back pain, right anterior thigh pain and hip flexor weakness. Magnetic resonance imaging (MRI) and computerized tomography (CT) myelography revealed an arachnoid cyst at T12-L1 level on the right side. At surgery, a nerve root was seen prolapsing into an extradural arachnoid cyst. The nerve root was replaced back into dural sac and the dural defect closed. At 20 months of follow-up, the patient continues to be asymptomatic with no evidence of recurrence on imaging. Replacing the prolapsed nerve root into the dural sac with meticulous closure of the dural defect could lead to good clinical outcome. We propose a modification to the popular classification of these lesions to better rationalize their surgical management. Classification of extradural arachnoid spinal cysts (Nabors's type 1) should be based on the presence or absence of dural communication. Sacral meningoceles (Nabors' type 1B) should be excluded from the classification as they have free communication with the thecal sac and are not true spinal cysts. PMID:19185984

Sangala, Jaypal Reddy; Uribe, Juan S; Park, Paul; Martinez, C; Vale, Fernando L



Evaluation of lumbosacral nerve root conduction in chickens by electrophysiological testing including high-resolution spinal magnetic stimulation.  


The value of avian models in peripheral nerve research recently became substantiated by the immunobiological similarity of avian inflammatory demyelinating polyradiculoneuropathy to human Guillain-Barré syndrome providing an alternative animal model for experimental autoimmune neuritis. As electrophysiologic evaluation of nerve roots is essential part of the diagnosis of polyradiculoneuropathies in humans, it would be favourable to have similar research methods available for juvenile chickens. Hence, this study was performed (1) to establish a tool-set that allows for reproducible evaluation of the tibial/sciatic nerve and its nerve roots, (2) to achieve age-matched reference values, and (3) to trace the kinetics of peripheral nerve maturation within chickens. Nine chickens underwent serial electrodiagnostic examinations between the age of 6 and 15 weeks. Several methods of sensory and motor nerve fiber stimulation of the tibial/sciatic nerve were tested and modified or established. Ultimately, scalp-recorded somatosensory evoked potentials, compound muscle action potentials elicited by tibial/sciatic nerve electrical as well as spinal magnetic stimulation and motor nerve conduction velocity were available for tibial/sciatic nerve and nerve root evaluation in chickens. Base values were obtained for all investigations and parameters. Results indicated that the maturation of the nerve fibers is incomplete up to the age of 15 weeks. The methods tested here provide an excellent tool-set for quantitative tibial/sciatic nerve and nerve root assessment in avian polyradiculoneuropathies, especially within the scope of longitudinal monitoring of the disease course. PMID:21074557

Bader, Sophie R; Fischer, Andrea; Emrich, Daniela; Juetting, Uta; Weyh, Thomas; Kaspers, Bernd; Matiasek, Kaspar



[Sciatica due to unusual causes: Tarlov cysts and nerve roots anomalies].  


Tarlov cysts and nerve roots anomalies usually involve lumbosacral roots and are often asymptomatic. MRI has enabled recognition of many conditions that used to be missed by CT or myelography investigations performed for back and leg pain. However, even without additional compressive impingement (disc hernia, spondylolisthesis or lumbar canal stenosis) these anomalies can be responsible for sciatica, motor deficit and bladder sphincter dysfunction. Tarlov cysts are perinervous dilatations of the dorsal root ganglion. CT and especially MRI can reveal these cysts and their precise relations with the neighboring structures. Delayed filling of the cysts can be visualized on the myelogram. MRI is more sensitive than CT myelography for a positive diagnosis of nerve root anomalies, a differential diagnosis with disc hernia and classification of these anomalies. Surgical treatment is indicated for symptomatic Tarlov cysts and nerve root anomalies resistant to conservative treatment. Better outcome is observed in patients with an additional compressive impingement component. We report two cases of sciatica: one caused by Tarlov cysts diagnosed by MRI and the other by nerve root anomalies diagnosed by CT myelography. In both cases, conservative treatment was undertaken. The clinical, radiological and therapeutic aspects of these disorders are discussed. PMID:18809189

Younes, M; Korbaa, W; Zrour, S; Bejia, I; Touzi, M; Bergaoui, N



The radio-radial nerve transfer for elbow extension restoration in C5 to C7 nerve root injury.  


Extension of the elbow is required to oppose gravity; however, activation of the triceps brachii is frequently underestimated during the surgical planning for brachial plexus injuries. This report aims to describe a novel technique of distal nerve transfer designed for elbow extension reconstruction in patients sustaining a C5-C7 nerve root injury. We report a patient sustaining a brachial plexus injury with triceps palsy and preserved finger extension motion; after careful intraneural dissection of the radial nerve, a fascicle innervating the extensor digitorum communis muscle was sectioned, derouted and connected to a motor branch to the lateral head of the triceps. Eleven months after surgery, elbow extension strength scored MRC M4. No deficits on finger extension were observed. PMID:22002181

Flores, Leandro Pretto



Increased Numbers of Thoracic Dorsal Root Axons in Rats Given Antibodies to Nerve Growth Factor  

NASA Astrophysics Data System (ADS)

Sensory axons were counted in untreated 1-month-old rats and in littermates that were injected with antibodies to nerve growth factor. There were 45 percent more unmyelinated and 17 percent more myelinated axons in dorsal roots of the fifth thoracic spinal segment in treated rats. This suggests that the number of sensory axons can be changed by postnatal inactivation of nerve growth factor.

Hulsebosch, C. E.; Coggeshall, R. E.; Perez-Polo, J. R.



[Physiological approach to peripheral neuropathy. Conventional nerve conduction studies and magnetic motor root stimulation].  


In this communication, I first show some points we should mind in the conventional peripheral nerve conduction studies and later present clinical usefulness of motor root stimulation for peripheral neuropathy. CONVENTIONAL NERVE CONDUCTION STUDIES (NCS): The most important point revealed by the conventional NCSs is whether neuropathy is due to axonal degeneration or demyelinating process. Precise clinical examination with this neurophysiological information leads us to a diagnosis and treatment. Poor clinical examination makes these findings useless. Long standing axonal degeneration sometimes induces secondary demyelination at the most distal part of involved nerves. On the other hand, severe segmental demyelination often provokes secondary axonal degeneration at distal parts to the site of demyelination. These secondary changes show the same abnormal neurophysiological findings as those of the primary involvement. We should be careful of this possibility when interpreting the results of NCS. NCS of sensory nerves is not good at revealing demyelinating process. Mild temporal dispersion of potentials often reduces an amplitude of SNAP or loss of responses, which usually suggests axonal degeneration, because of short duration of sensory nerve potentials. MOTOR ROOT STIMULATION IN PERIPHERAL NEUROPATHY: Magnetic stimulation with a coil placed over the spine activates motor roots and evokes EMG responses from upper and lower limb muscles. The site of activation with this method was determined to be where the motor roots exit from the spinal canal (intervertebral foramina) (J Neurol Neurosurg Psychiatry 52 (9): 1025-1032, 1989) because induced currents are very dense at such a foramen made by electric resistant bones. In several kinds of peripheral neuropathy, this method has been used to detect a lesion at a proximal part of the peripheral nerves which can not be detected by the conventional NCSs. I present a few cases in whom motor root stimulation had a clinical merit. In a patient with neuralgic amyotrophy, motor root stimulation disclosed a conduction block between the cervical intervertebral foramen and brachial plexus which was not detected by conventional NCSs. Motor root stimulation clearly revealed demyelination in a patient with CIDP in whom sural nerve biopsy findings suggested axonal degeneration, that must be secondary to demyelination. In a patient with tomacular neuropathy, magnetic stimulation revealed conduction delay in the spinal nerve within the spinal canal (Clin Neurol (Jap), 28: 447-452, 1988). Based on the above results, combination of NCSs and magnetic motor root stimulation must brush up the neurophysiological approach to peripheral neuropathy. PMID:15651350

Ugawa, Yoshikazu



Drainage of molecules from subarachnoid space to spinal nerve roots and peripheral nerve of the rat. A study based on Evans blue-albumin and lanthanum as tracers.  


The purpose of the present investigation was to find out if a compound injected into the spinal subarachnoid space, after having entered ventral and dorsal nerve roots, can be traced to the epineurial-perineurial sheaths and the endoneurium of peripheral nerves. This would indicate a centrifugal movement of substances from the cerebrospinal fluid along nerves; one route of drainage of cerebrospinal fluid which in the past has been widely discussed. In vivo studies were made using Evans blue-albumin and lanthanum chloride as tracers. Evans blue-albumin is macromolecular in size and emits a red fluorescence after exposure to ultraviolet light. Lanthanum ions are small and easily visible in the electron microscope. The tracers were injected into the cervical subarachnoid space and 15 min to 24 h later samples from roots, dorsal root ganglia, proximal part of spinal nerves and the median nerves were taken and further processed for detection of tracers. Fluorescence microscopy from samples removed 15 min and 24 h after the injection of Evans blue-albumin showed a red fluorescence of low intensity in the endoneurium of nerve roots, ganglia and proximal spinal nerve. After 24 h also the median nerve elicited some fluorescence. The sheaths around these structures were also fluorescent. Lanthanum was detected between cell layers of the nerve root sheath as well as inside the nerve root parenchyma. In about 50% of the samples from dorsal root ganglia extracellular lanthanum was found in the capsule. The tracer was also found in the epineurium of 50% of the spinal nerves and occasionally in the perineurium.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7508671

Pettersson, C A



Migratory Reed Warblers Need Intact Trigeminal Nerves to Correct for a 1,000 km Eastward Displacement  

PubMed Central

Several studies have shown that experienced night-migratory songbirds can determine their position, but it has remained a mystery which cues and sensory mechanisms they use, in particular, those used to determine longitude (east–west position). One potential solution would be to use a magnetic map or signpost mechanism like the one documented in sea turtles. Night-migratory songbirds have a magnetic compass in their eyes and a second magnetic sense with unknown biological function involving the ophthalmic branch of the trigeminal nerve (V1). Could V1 be involved in determining east–west position? We displaced 57 Eurasian reed warblers (Acrocephalus scirpaceus) with or without sectioned V1. Sham operated birds corrected their orientation towards the breeding area after displacement like the untreated controls did. In contrast, V1-sectioned birds did not correct for the displacement. They oriented in the same direction after the displacement as they had done at the capture site. Thus, an intact ophthalmic branch of the trigeminal nerve is necessary for detecting the 1,000 km eastward displacement in this night-migratory songbird. Our results suggest that V1 carries map-related information used in a large-scale map or signpost sense that the reed warblers needed to determine their approximate geographical position and/or an east–west coordinate.

Heyers, Dominik; Mouritsen, Henrik



Nerve root injury severity differentially modulates spinal glial activation in a rat lumbar radiculopathy model: considerations for persistent pain  

Microsoft Academic Search

Nerve root deformation magnitude affects behavioral sensitivity and spinal cytokine expression in a lumbar radiculopathy model. Despite evidence suggesting spinal glia play a role in persistent pain, no study has examined the relationship between injury severity in painful radiculopathy and spinal glial activation. This study quantified local in vivo biomechanics for nerve root injury, describing effects on temporal glial activation.

Beth A Winkelstein; Joyce A DeLeo



Nerve root decompression without fusion in spondylolytic spondylolisthesis: long-term results of Gill’s procedure  

Microsoft Academic Search

Nerve root decompression with instrumented fusion is currently most commonly performed in the treatment of patients with spondylolytic spondylolisthesis. The relationship between successful fusion and clinical outcome remains controversial, thereby questioning the necessity of fusion. Nerve root decompression without fusion, i.e. Gill’s procedure, might be a less invasive surgical alternative with comparable clinical outcome. The objective of this study is

Mark Arts; Willem Pondaag; Wilco Peul; Raph Thomeer



Effects of scan circle displacement in optical coherence tomography retinal nerve fibre layer thickness measurement: a RNFL modelling study  

Microsoft Academic Search

ObjectiveTo study the effect of optical coherence tomography (OCT) scan circle displacement on retinal nerve fibre layer (RNFL) measurement errors using cubic spline models.MethodsForty-nine normal subjects were included in the analysis. In one randomly selected eye in each subject, RNFL thickness around the optic disc was measured by taking 16 circular scans of different sizes (scan radius ranged from 1

C Y L Cheung; C K F Yiu; R N Weinreb; D Lin; H Li; A Y Yung; C P Pang; D S C Lam; C K S Leung; CKS Leung



Asymmetrical displacement currents in the membrane of frog myelinated nerve: Early time course and effects of membrane potential  

Microsoft Academic Search

1.Asymmetrical displacement currents were studied in myelinated nerve fibres fromRana esculenta with a voltage clamp technique.2.For brief pulses symmetrical with respect to a holding potential of -97 mV, the asymmetry current flowing during pulses (on-response) exhibited a rising phase to a peak followed by an approximately exponential decline. After the pulses the rising phase in the off-response could not be

W. Nonner; E. Rojas; R. Stämpfli



Therapeutic efficacy of selective nerve root blocks in the treatment of lumbar radicular leg pain.  


The objective of this study was to investigate the clinical effectiveness of nerve root blocks (i.e., periradicular injection of bupivacaine and triamcinolone) for lumbar monoradiculopathy in patients with a mild neurological deficit. We have retrospectively analysed 30 patients (29-82 years) with a minor sensory/motor deficit and an unequivocal MRI finding (20 disc herniations, 10 foraminal stenoses) treated with a selective nerve root block. Based on the clinical and imaging findings, surgery (decompression of the nerve root) was justifiable in all cases. Twenty-six patients (87%) had rapid (1-4 days) and substantial regression of pain, five required a repeat injection. 60% of the patients with disc herniation or foraminal stenosis had permanent resolution of pain, so that an operation was avoided over an average of 16 months (6-23 months) follow-up. Nerve root blocks are very effective in the non-operative treatment of minor monoradiculopathy and should be recommended as the initial treatment of choice for this condition. PMID:11383229

Narozny, M; Zanetti, M; Boos, N



Unilateral spondylolysis associated with spina bifida occulta and nerve root compression.  


Three patients with unilateral spondylolysis and spina bifida occulta were treated with hemilaminectomy, pseudarthrosis excision, and bilateral posterolateral fusion. All patients had persistent radiating leg pain, a positive sciatic tension sign, an objective neurologic deficit, and neuroradiographic studies that confirmed isolated L5 nerve root entrapment at the pars defect. Postoperatively, all patients noted complete relief of their radicular symptoms. PMID:2205929

Burkus, J K



Nerve root anomalies: implications for transforaminal lumbar interbody fusion surgery and a review of the Neidre and Macnab classification system.  


Lumbar nerve root anomalies are uncommon phenomena that must be recognized to avoid neural injury during surgery. The authors describe 2 cases of nerve root anomalies encountered during mini-open transforaminal lumbar interbody fusion (TLIF) surgery. One anomaly was a confluent variant not previously classified; the authors suggest that this variant be reflected in an amendment to the Neidre and Macnab classification system. They also propose strategies for identifying these anomalies and avoiding injury to anomalous nerve roots during TLIF surgery. Case 1 involved a 68-year-old woman with a 2-year history of neurogenic claudication. An MR image demonstrated L4-5 stenosis and spondylolisthesis and an L-4 nerve root that appeared unusually low in the neural foramen. During a mini-open TLIF procedure, a nerve root anomaly was seen. Six months after surgery this patient was free of neurogenic claudication. Case 2 involved a 60-year-old woman with a 1-year history of left L-4 radicular pain. Both MR and CT images demonstrated severe left L-4 foraminal stenosis and focal scoliosis. Before surgery, a nerve root anomaly was not detected, but during a unilateral mini-open TLIF procedure, a confluent nerve root was identified. Two years after surgery, this patient was free of radicular pain. PMID:23905960

Burke, Shane M; Safain, Mina G; Kryzanski, James; Riesenburger, Ron I



Macrophage-Mediated Dorsal Root Ganglion Damage Precedes Altered Nerve Conduction in SIV-Infected Macaques  

PubMed Central

Peripheral neuropathy is the most common neurological complication of HIV-1 infection, affecting over one-third of infected individuals, including those treated with antiretroviral therapy. To study the pathogenesis of HIV-induced peripheral nervous system disease, we established a model in which SIV-infected macaques developed changes closely resembling alterations reported in components of the sensory pathway in HIV-infected individuals. Significant declines in epidermal nerve fiber density developed in SIV-infected macaques, similar to that of HIV-infected individuals with neuropathy. Changes in dorsal root ganglia (DRG) included macrophage infiltration, SIV replication in macrophages, immune activation of satellite cells, and neuronal loss. To determine whether dorsal root ganglion damage was associated with altered nerve function, we measured unmyelinated C-fiber conduction velocities (CV) in nerves of SIV-infected macaques and compared CV changes with DRG alterations. Twelve weeks postinoculation, SIV-infected macaques had significantly lower C-fiber conduction velocity in sural nerves than uninfected animals and the magnitude of conduction velocity decline correlated strongly with extent of DRG macrophage infiltration. Thus, injury to neurons in the DRG—mediated by activated macrophages—preceded altered conduction of unmyelinated nerve fibers in SIV-infected macaques, suggesting that macrophage-mediated DRG damage may be the initiating event in HIV-induced sensory neuropathy.

Laast, Victoria A.; Shim, Beom; Johanek, Lisa M.; Dorsey, Jamie L.; Hauer, Peter E.; Tarwater, Patrick M.; Adams, Robert J.; Pardo, Carlos A.; McArthur, Justin C.; Ringkamp, Matthias; Mankowski, Joseph L.



Macrophage-mediated dorsal root ganglion damage precedes altered nerve conduction in SIV-infected macaques.  


Peripheral neuropathy is the most common neurological complication of HIV-1 infection, affecting over one-third of infected individuals, including those treated with antiretroviral therapy. To study the pathogenesis of HIV-induced peripheral nervous system disease, we established a model in which SIV-infected macaques developed changes closely resembling alterations reported in components of the sensory pathway in HIV-infected individuals. Significant declines in epidermal nerve fiber density developed in SIV-infected macaques, similar to that of HIV-infected individuals with neuropathy. Changes in dorsal root ganglia (DRG) included macrophage infiltration, SIV replication in macrophages, immune activation of satellite cells, and neuronal loss. To determine whether dorsal root ganglion damage was associated with altered nerve function, we measured unmyelinated C-fiber conduction velocities (CV) in nerves of SIV-infected macaques and compared CV changes with DRG alterations. Twelve weeks postinoculation, SIV-infected macaques had significantly lower C-fiber conduction velocity in sural nerves than uninfected animals and the magnitude of conduction velocity decline correlated strongly with extent of DRG macrophage infiltration. Thus, injury to neurons in the DRG-mediated by activated macrophages-preceded altered conduction of unmyelinated nerve fibers in SIV-infected macaques, suggesting that macrophage-mediated DRG damage may be the initiating event in HIV-induced sensory neuropathy. PMID:21924225

Laast, Victoria A; Shim, Beom; Johanek, Lisa M; Dorsey, Jamie L; Hauer, Peter E; Tarwater, Patrick M; Adams, Robert J; Pardo, Carlos A; McArthur, Justin C; Ringkamp, Matthias; Mankowski, Joseph L



Diffusion tensor imaging and T2 relaxometry of bilateral lumbar nerve roots: feasibility of in-plane imaging.  


Lower back pain is a common problem frequently encountered without specific biomarkers that correlate well with an individual patient's pain generators. MRI quantification of diffusion and T2 relaxation properties may provide novel insight into the mechanical and inflammatory changes that occur in the lumbosacral nerve roots in patients with lower back pain. Accurate imaging of the spinal nerve roots is difficult because of their small caliber and oblique course in all three planes. Two-dimensional in-plane imaging of the lumbosacral nerve roots requires oblique coronal imaging with large field of view (FOV) in both dimensions, resulting in severe geometric distortions using single-shot echo planar imaging (EPI) techniques. The present work describes initial success using a reduced-FOV single-shot spin-echo EPI acquisition to obtain in-plane diffusion tensor imaging (DTI) and T2 mapping of the bilateral lumbar nerve roots at the L4 level of healthy subjects, minimizing partial volume effects, breathing artifacts and geometric distortions. A significant variation in DTI and T2 mapping metrics is also reported along the course of the normal nerve root. The fractional anisotropy is statistically significantly lower in the dorsal root ganglia (0.287?±?0.068) than in more distal regions in the spinal nerve (0.402?±?0.040) (p?root ganglia (78.0?±?11.9?ms) than in more distal regions in the spinal nerve (59.5?±?7.4?ms) (p?nerve root DTI and T2 properties using the proposed methodology may identify the specific site of any degenerative and inflammatory changes along the nerve roots of patients with lower back pain. PMID:23208676

Karampinos, Dimitrios C; Melkus, Gerd; Shepherd, Timothy M; Banerjee, Suchandrima; Saritas, Emine U; Shankaranarayanan, Ajit; Hess, Christopher P; Link, Thomas M; Dillon, William P; Majumdar, Sharmila



Microscopic clusters of sensory neurons in c1 spinal nerve roots and in the c1 level of the spinal accessory nerve in adult humans.  


This study examined C1 spinal nerve roots and their anastomotic connections with the spinal accessory nerve for histological evidence of sensory neurons in adult humans. C1 spinal nerves and roots with the adjacent segments of the spinal accessory nerve and the spinal cord were dissected en bloc from cadaveric specimens, and prepared for histological study. Results show that in 39.3% of specimens studied, no sensory component to the C1 spinal nerve could be identified. The C1 dorsal root was present 35.7% of the time, and when present it always contained neuronal cell bodies. In the remaining specimens, the sensory contribution to the C1 spinal nerve came through an anastomotic connection with the spinal accessory nerve. The investigators were able to identify clusters of neuronal cell bodies along the spinal accessory nerve at the level of C1 in 100% of the specimens examined. Anat Rec, 296:1588-1593, 2013. © 2013 Wiley Periodicals, Inc. PMID:23929774

Hovorka, Michelle S; Uray, Nandor J



Correlative study of nerve root palsy and cervical posterior decompression laminectomy and internal fixation.  


This study investigates the probable causes of nerve root palsy through the retrospective study of pre- and postoperative cervical curvature change for patients with cervical spondylosis and incidences of nerve root palsy. A consecutive series of 91 patients with cervical compressive myelopathy treated by laminectomy and internal fixation were reviewed. Nerve root palsy developed in 21 of 91 patients (23%) (group A). The other 70 patients, 41 men and 29 women, were chosen as controls (group B). A neutral lateral cervical spine radiograph was taken of all patients. The overall curvature of the cervical spine, the cervical curvature index, and the change rate were measured and compared.The pre- and postoperative change rate of cervical curvatures in groups A and B was 19.17+/-7.62 and 18.03+/-7.62, respectively. The difference was not statistically significant (P>.05). The pre- and postoperative cervical curvature index change rate in groups A and B was 17.52+/-3.46 and 12.43+/-4.12, respectively. There were statistically significant differences between the 2 groups (P<. 05). This indicated the cervical alignment of patients in group A was changed greatly by traction during operation.In this study, we found that tethering the nerve root caused C5 palsy, but excessive intraoperative traction and the use of internal fixation may be one of the most important reasons for this. The cervical curvature index change rate reflected both a change in cervical height and a change in the overall cervical curvature. It is more sensitive in reflecting the degree of cervical traction and the change of the cervical alignment. PMID:20704111

Liu, Tielong; Zou, Weiwei; Han, Yu; Wang, Yan



The Efficacy and Persistence of Selective Nerve Root Block under Fluoroscopic Guidance for Cervical Radiculopathy  

PubMed Central

Study Design Retrospective study. Objectives To investigate the outcomes of fluoroscopically guided selective nerve root block as a nonsurgical treatment for cervical radiculopathy. Overview of Literature Only a few studies have addressed the efficacy and persistence of cervical nerve root block. Methods This retrospective study was conducted on 28 consecutive patients with radicular pain due to cervical disc disease or cervical spondylosis. Myelopathy was excluded. Cervical nerve root blocks were administered every 2 weeks, up to 3 times. Outcomes were measured by comparing visual analogue scale (VAS) scores, patient satisfaction, and medication usage before the procedure and at 1 week and 3, 6, and 12 months after the procedure. In addition, complications associated with the procedure and need for other treatments were evaluated. Results The average preoperative VAS score was 7.8 (range, 5 to 10), and this changed to 2.9 (range, 1 to 7) at 3 months and 4.6 (range, 2 to 7) at 12 months. Patient satisfaction was 71% at 3 months and 50% at 12 months. Five patients used medication at 3 months, whereas 13 used medication at 12 months. Average symptom free duration after the procedure was 7.8 months (range, 1 to 12 months). Two patients were treated surgically. Only two minor complications were noted; transient ptosis with Horner's syndrome and transient causalgia. Conclusions Although selective nerve root block for cervical radiculopathy is limited as a definitive treatment, it appears to be useful in terms of providing relief from radicular pain in about 50% of patients at 12 months.

Chung, Jae-Yoon; Seo, Hyoung-Yeon; Kim, Sung-Kyu; Cho, Kyu-Jin



Increased TRPA1, TRPM8, and TRPV2 expression in dorsal root ganglia by nerve injury  

Microsoft Academic Search

Thermosensitive TRP channels display unique thermal responses, suggesting distinct roles mediating sensory transmission of temperature. However, whether relative expression of these channels in dorsal root ganglia (DRG) is altered in nerve injury is unknown. We developed a multiplex ribonuclease protection assay (RPA) to quantify rat TRPV1, TRPV2, TRPV3, TRPV4, TRPA1, and TRPM8 RNA levels in DRG. We used the multiplex

J. Frederick; M. E. Buck; D. J. Matson; D. N. Cortright



Bone metastases with nerve root compression as a late complication in patient with epithelial pleural mesothelioma  

PubMed Central

Malignant pleural mesothelioma (MPM) is an aggressive tumor with dismal prognoses and poor response to treatments. The most frequent symptoms are due to local invasion. Distant metastases are not uncommon and usually appear at late stage of the disease. However, metastases in bone have rarely been well documented. Here we report the case of a MPM patient with nerve root compression due to bone metastases 18 months after the first diagnoses of MPM.

Farinas, Lorena; Stejpanovic, Neda; Martinez, Pablo; Martinez, Alex; Zamora, Esther; Montero, Maria Angeles; Felip, Enriqueta



Bone morphogenetic protein-induced inflammatory cyst formation after lumbar fusion causing nerve root compression.  


Bone morphogenetic protein (BMP) has been reported to cause early inflammatory changes, ectopic bony formation, adjacent level fusion, radiculitis, and osteolysis. The authors describe the case of a patient who developed inflammatory fibroblastic cyst formation around the BMP sponge after a lumbar fusion, resulting in compressive lumbar radiculopathy. A 70-year-old woman presented with left L-4 and L-5 radiculopathy caused by a Grade I spondylolisthesis with a left herniated disc at L4-5. She underwent a minimally invasive transforaminal lumbar interbody fusion with BMP packed into the interbody cage at L4-5. Her neurological symptoms resolved immediately postoperatively. Six weeks later, the patient developed recurrence of radiculopathy. Radiological imaging demonstrated an intraspinal cyst with a fluid-fluid level causing compression of the left L-4 and L-5 nerve roots. Reexpoloration of the fusion was performed, and a cyst arising from the posterior aspect of the cage was found to compress the axilla of the left L-4 nerve root and the shoulder of the L-5 nerve root. The cyst was decompressed, and the wall was partially excised. A collagen BMP sponge was found within the cyst and was removed. Postoperatively, the patient's radiculopathy resolved and she went on to achieve interbody fusion. Bone morphogenetic protein can be associated with inflammatory cyst formation resulting in neural compression. Spine surgeons should be aware of this complication in addition to the other reported BMP-related complications. PMID:22176433

Choudhry, Osamah J; Christiano, Lana D; Singh, Rahul; Golden, Barbara M; Liu, James K



The potential for salmon fibrin and thrombin to mitigate pain subsequent to cervical nerve root injury  

PubMed Central

Nerve root compression is a common cause of radiculopathy and induces persistent pain. Mammalian fibrin is used clinically as a coagulant but presents a variety of risks. Fish fibrin is a potential biomaterial for neural injury treatment because it promotes neurite outgrowth, is non-toxic, and clots readily at lower temperatures. This study administered salmon fibrin and thrombin following nerve root compression and measured behavioral sensitivity and glial activation in a rat pain model. Fibrin and thrombin each significantly reduced mechanical allodynia compared to injury alone (p<0.02). Painful compression with fibrin exhibited allodynia that was not different from sham for any day using stimulation by a 2 g filament; allodynia was only significantly different (p<0.043) from sham using the 4 g filament on days 1 and 3. By day 5, responses for fibrin treatment decreased to sham levels. Allodynia following compression with thrombin treatment were unchanged from sham at any time point. Macrophage infiltration at the nerve root and spinal microglial activation were only mildly modified by salmon treatments. Spinal astrocytic expression decreased significantly with fibrin (p<0.0001) but was unchanged from injury responses for thrombin treatment. Results suggest that salmon fibrin and thrombin may be suitable biomaterials to mitigate pain.

Weisshaar, Christine L.; Winer, Jessamine P.; Guarino, Benjamin B.; Janmey, Paul A.; Winkelstein, Beth A.



Microsurgical nerve root canal widening without fusion for lumbosacral intervertebral foraminal stenosis: technical notes and early results  

Microsoft Academic Search

We describe a technique for microsurgical widening of the nerve root canal in the lumbosacral spine. We also report our early results in 31 patients (19 men and 12 women; average follow-up, 3.2 years) with such foraminal stenosis but without osseous defects in the pars interarticularis and\\/or spondylolisthesis. The affected nerve root was decompressed by interlaminar medial foraminotomy followed by

Hisatoshi Baba; Kenzo Uchida; Yasuhisa Maezawa; Nobuaki Furusawa; Yasuhiro Okumura; Shinichi Imura



Arteriovenous Fistula in a Nerve Root of the Cauda Equina Fed by a Proximal Radiculo-Medullary Artery  

PubMed Central

Summary While there have been a few reports on cases of intradural spinal arteriovenous fistula located on the filum terminale, no cases of its location in a nerve root of the cauda equina have been reported to date. We describe two such cases and describe the intraoperative findings. A 40-year-old man presented weakness of his left leg. Another 62-year-old man presented paraparesis dominantly in his left leg with urinary hesitation. In both cases, spinal T2-weighted magnetic resonance images showed edema of the spinal cord, indicating a flow void around it. Digital subtraction angiography disclosed an anterior radicular artery branching from the anterior spinal artery on the surface of the conus medullaris and a turnaround vein running in the opposite direction within the cauda equina. In the first patient, while the feeding artery running along a nerve root was detected, the draining vein and the fistula were not identified at first sight. An incision into the respective nerve root exposed their location within it. In the second patient, unlike the first case, the feeding artery and the fistula were buried in a nerve root, while the draining vein was running along the nerve’s surface. In both cases, permanent clips were applied to the draining vein closest to the fistula. The recognition of a hidden fistulous point in a nerve root of the cauda equina is essential for successful obliteration of the fistula.

Ohtonari, T.; Ota, S.; Nishihara, N.; Suwa, K.; Ota, T.; Sekihara, Y.; Tanaka, A.; Koyama, T.



An improved method for avulsion of lumbar nerve roots as an experimental model of nitric oxide-mediated neuronal degeneration  

Microsoft Academic Search

A root avulsion lesion on the spinal nerve of adult animals is a useful technique to make a model for axotomy-induced motoneuronal degeneration, which is thought to be mediated by nitric oxide (NO). Here, we show a simplified version of extravertebral avulsion in the young adult rat. The L4 nerve always runs under the transverse process of the L5 vertebra,

Jian-wen He; Kazuho Hirata; Akio Kuraoka; Masaru Kawabuchi



Evaluation of lumbosacral nerve root conduction in chickens by electrophysiological testing including high-resolution spinal magnetic stimulation  

Microsoft Academic Search

The value of avian models in peripheral nerve research recently became substantiated by the immunobiological similarity of avian inflammatory demyelinating polyradiculoneuropathy to human Guillain–Barré syndrome providing an alternative animal model for experimental autoimmune neuritis. As electrophysiologic evaluation of nerve roots is essential part of the diagnosis of polyradiculoneuropathies in humans, it would be favourable to have similar research methods available

Sophie R. Bader; Andrea Fischer; Daniela Emrich; Uta Juetting; Thomas Weyh; Bernd Kaspers; Kaspar Matiasek



Analysis of bladder related nerve cuff electrode recordings frompreganglionic pelvic nerve and sacral roots in pigs  

Microsoft Academic Search

Electrical stimulation of appropriate lower urinary tract (LUT) nerves\\u000d\\u000a\\u0009may be used in bladder dysfunction to achieve continence and abolish\\u000d\\u000a\\u0009hyper-reflexic detrusor contractions. It can also be used for consequent\\u000d\\u000a\\u0009emptying of the bladder. To control the time course of the described\\u000d\\u000a\\u0009functional phases, knowledge of bladder sensory information is needed.\\u000d\\u000a\\u0009We investigated if the latter could be extracted from

S. Jezernik; J. G. Wen; N. J. Rijkhoff; J. C. Djurhuus; T. Sinkjaer



Extrachromosomal DNA of pea (Pisum sativum) root-tip cells replicates by strand displacement  

SciTech Connect

In cultured pea roots there is extrachromosomal DNA associated with cells that differentiate from the G/sub 2/ phase of the cell cycle that is absent from those that differentiate from the G/sub 1/ phase. The authors examined this extrachromosomal DNA by electron microscopy and found that it consisted of three types: (i) double-stranded linear molecules with single-stranded branches (74%), (ii) double-stranded molecules without branches (26%), and (iii) free single-stranded molecules. The double-stranded molecules with or without branches were similar in length, having a modal length of 10-15 The free single-stranded molecules were shorter and had a mean length of 3.8 The length of the branches attached to the duplex molecules was only slightly less than that of the free form. The duplex molecules with branches were interpreted as configurations reflecting an ongoing strand-displacement process that results in free single-stranded molecules. Finally, measurements on duplex molecules with multiple branches suggested that the extrachromosomal DNA may exist in the form of tandemly repeated sequences. 8 references, 8 figures.

Krimer, D.B.; Van't Hof, J.



Removal of an iliosacral screw entrapping the L5 nerve root after failed posterior pelvic ring fixation: a case report.  


We present a case of a pelvic ring fracture that was originally treated with anterior symphyseal plating and a misplaced percutaneous iliosacral screw. The anterior extraosseus portion of the misplaced 7.3-mm cannulated screw irritated the L5 nerve root, resulting in a radiculopathy. Subsequent surgery involved and mandated removing the bent screw after open identification and protection of the L5 nerve root to avoid further nerve damage; the sacroiliac joint was subsequently debrided and fused. This case represents a complication of acute percutaneous iliosacral screw fixation of pelvic ring injuries and the subsequent strategy for successful salvage. PMID:17621002

Weil, Yoram A; Nousiainen, Markku T; Helfet, David L



Surgical treatment options and management strategies of metastatic renal cell carcinoma to the lumbar spinal nerve roots.  


Spinal nerve root metastasis of renal cell carcinoma is a rare occurrence. In addition to treatment of the primary lesion, surgical resection of the nerve root metastasis, occasionally with sacrifice of the involved nerve, is the accepted standard of treatment. Resection often resolves presenting motor and pain symptoms due to relief of neural compression. We describe two patients with nerve root metastasis of renal cell carcinoma and their management. While locally advanced and metastatic renal cell carcinoma has been shown to be chemo- and radio-resistant, immunotherapy is a promising treatment. Given the high prevalence of systemic disease in patients with intradural metastases, systemic (and possibly intracranial) imaging can be used to identify other potential areas of disease. PMID:23931936

Strong, Christian; Yanamadala, Vijay; Khanna, Arjun; Walcott, Brian P; Nahed, Brian V; Borges, Lawrence F; Coumans, Jean-Valery C E



Nerve root infiltration of the first sacral root with MRI guidance.  


The purpose of this clinical trial was to describe the methodology and evaluate the accuracy of optical tracking-based magnetic resonance (MR)-guided infiltration of the first sacral (S1) root. Thirty-five infiltrations were performed on 34 patients with a 0. 23-T open C-arm magnet installed in a fully equipped operation room with large-screen (36 inches) display and optical navigator utilizing infrared passive tracking. T1 and T2 fast spin-echo (FSE) images were used for localizing the target and fast field echo for monitoring the procedure. Saline as contrast agent in single-shot (SS)FSE images gave sufficient contrast-to-noise ratio. Twenty-four patients had unoperated L5/S1 disc herniation, and 10 had S1 root irritation after failed back surgery. Needle placement was successful in 97% of the cases, and no complications occurred. Outcome was evaluated 1-6 months (mean 2.2 months) after the procedure and was comparable to that of other studies using fluoroscopy or computed tomography guidance. MR-guided placement of the needle is an accurate technique for first sacral root infiltration. PMID:11042636

Ojala, R; Vahala, E; Karppinen, J; Klemola, R; Blanco-Sequeiros, R; Vaara, T; Tervonen, O



Cervical foraminal selective nerve root block: a 'two-needle technique' with results  

PubMed Central

Several techniques have been described for selective nerve root blocks. We describe a novel ‘two-needle technique’, performed through the postero-lateral route with the patient in lateral position under C-arm guidance. The aim of the current study is to highlight the effectiveness and safety of cervical selective nerve root block for radiculopathy using this technique. We present results of a retrospective 2-year follow-up study of 33 injections carried out on 33 patients with radiculopathy due to cervical disc disease and or foraminal stenosis using this procedure. Patients with myelopathy, gross motor weakness and any other pathology were excluded. The outcome was measured comparing ‘Visual Analogue Score’ (VAS) and ‘Neck Disability Index’ (NDI) before the procedure with those at 6 weeks and 12 months after the procedure. Thirty patients were included in the final analysis. Average pre-operative VAS score was 7.4 (range 5–10), which improved to 2.2 (range 0–7) at 6 weeks and 2.0 (range 0–4) at 1 year and the mean NDI score prior to intervention was 66.9 (range 44–84), which improved to 31.7 (range 18–66) at 6 weeks and 31.1 (range 16–48) at 1 year. The improvements were statistically significant. Patients with involvement of C6 or C7 nerve roots responded slightly better at 6 weeks with regards to VAS improvement. Mean duration of radiation exposure during the procedure was 27.8 s (range 10–90 s). Only minor complications were noted—transient dizziness in two and transient nystagmus in one patient. Our ‘two-needle technique’ is a new, safe and effective non-surgical treatment for cervical radiculopathy.

Gowda, Veda



Displaced calcium hydroxide paste causing inferior alveolar nerve paraesthesia: report of a case  

Microsoft Academic Search

A patient presented with an intraoral red, painful, and hard swelling in the lower right jaw. Radiographs showed a 2 × 1 cm area of radiopaque material surrounding the apex of the second premolar. The material, according to the patient's dentist, was calcium hydroxide paste used as a temporary dressing material in the root canal. The patient developed paraesthesia in

Fredrik K. E. K Ahlgren; Anne Christine Johannessen; Sølve Hellem



Root negative gravitropism is accompanied with displacing of columella amyloplasts to the statocyte upper longitudinal cell wall  

NASA Astrophysics Data System (ADS)

Recently it was shown that roots reveal negative gravitropism in the weak combined magnetic field (CMF) with the frequency resonance to the cyclotron frequency of Ca2+ ions. A negative gravitropic reaction in the CMF occurs by a usual physiological process. Experiments in the CMF confirmed that gravitropism is plastid-based and Ca2+ ions participate in this process. Unlike control, amyloplasts-statoliths are not displacing on the lower side of a gravistimulated root but tend to group in the center of a statocyte during 30 min under gravistimulation in the CMF. In an hour of gravistimulation, they are localized near one of the statocyte longitudinal wall. Now we determined that amyloplasts are localized along the statocyte upper longitudinal side. It is of a special interest that a root is bending to the same direction with displacing of amyloplasts: in positive gravitropism - downwards, in negative gravitropism - upwards. On the basis of the obtained data there is a question, what forces promote displacing of amyloplasts against a gravitational vector? In the paper, three possible explanations are discussed: 1) CMF + Ca2+ action on the distribution of elastic forces in cytoskeleton, 2) CMF + Ca2+ action on the distribution of electric field in statocytes, and 3) CMF action on energy and direction of Ca2+ ion rotation according to the ion cyclotron resonance model that can lead to paradoxical Ca2+ redistribution.

Kordyum, Elizabeth; Sobol, Margaryta; Kalinina, Yana; Bogatina, Nina; Kondrachuk, Alexander


Headache in patients with cervical radiculopathy: a prospective study with selective nerve root blocks in 275 patients  

PubMed Central

Since many years we routinely use diagnostic selective nerve root blocks (SNRB) at our department when evaluating patients with cervical radiculopathy. Frequently patients who also presented with headache reported that the headache disappeared when the nerve root responsible for the radicular pain was blocked with local anaesthetics. Headache has been described as a companioning symptom related to cervical radiculopathy but has never before been evaluated with SNRB performed in the lower cervical spine. For this reason we added to our routine an evaluation of the response from the SNRB on headache in patients with cervical radiculopathy. The aim was to describe the frequency of headache in patients with cervical radiculopathy and its response to a selective nerve root block of the nerve root/roots responsible for the radiculopathy. Can nerve root compression in the lower cervical spine produce headache? In this consecutive series of 275 patients with cervical radiculopathy, 161 patients reported that they also suffered from daily or recurrent headache located most often unilaterally on the same side as the radiculopathy. All patients underwent a careful clinical examination by a neurosurgeon and a MRI of the cervical spine. The significantly compressed root/roots, according to the MRI, underwent SNRB with a local anaesthetic. The effect of the nerve root block on the radiculopathy and the headache was carefully noted and evaluated by a physiotherapist using visual analogue scales (VAS) before and after the SNRB. All patients with headache had tender points in the neck/shoulder region on the affected side. Patients with headache graded significantly more limitations in daily activities and higher pain intensity in the neck/shoulder/arm than patients without headache. After selective nerve root block, 59% of the patients with headache reported 50% or more reduction of headache and of these 69% reported total relief. A significant correlation was seen between reduced headache intensity and reduced pain in the neck, shoulder and arm. The result indicates that cervical root compression from degenerative disease in the lower cervical spine producing radiculopathy might also induce headache.

Carlsson, Jane Y.; Anderberg, Leif



Cervical nerve root decompression by lateral approach as salvage operation after failed anterior transdiscal surgery: technical case report.  


Cervical nerve root compression caused by disco-osteophytic changes is classically operated by anterior transdiscal approach with disc replacement. If compression persists or recurs, reoperation via the same surgical route may be difficult, because of scar tissue and/or implants. An alternative approach may be necessary. We recommend the lateral cervical approach (retrojugular) as salvage operation in such cases. We report a patient with cervical nerve root compression operated by anterior transdiscal approach with plate and bone graft. As some compression persisted clinically and radiologically, the patient was re-operated via a lateral approach. The surgical access was free of scar tissue. The arthrodesis could be left intact and did not prevent effective nerve root decompression. The patient became asymptomatic. The lateral cervical approach (retrojugular) as reported here, is an excellent alternative pathway if reoperation after anterior transdiscal surgery with disc replacement becomes necessary. PMID:19449041

Cornelius, Jan Frédérick; George, Bernard



Brain-Derived Neurotrophic Factor Increases in the Uninjured Dorsal Root Ganglion Neurons in Selective Spinal Nerve Ligation Model  

Microsoft Academic Search

Nerve growth factor (NGF) and brain-derived neurotrophic fac- tor (BDNF) are two major members of the neurotrophin family. Using immunohistochemistry and in situ hybridization histo- chemistry, we examined the effect of L5 spinal nerve ligation (SPNL), a neuropathic pain model, on the expression of BDNF in the uninjured L4 dorsal root ganglion (DRG). After L5 SPNL, both immunoreactivity for BDNF

Tetsuo Fukuoka; Eiji Kondo; Yi Dai; Norio Hashimoto; Koichi Noguchi



Differing alterations of sodium currents in small dorsal root ganglion neurons after ganglion compression and peripheral nerve injury  

Microsoft Academic Search

Voltage-gated sodium channels play important roles in modulating dorsal root ganglion (DRG) neuron hyperexcitability and hyperalgesia after peripheral nerve injury or inflammation. We report that chronic compression of DRG (CCD) produces profound effect on tetrodotoxin-resistant (TTX-R) and tetrodotoxin-sensitive (TTX-S) sodium currents, which are different from that by chronic constriction injury (CCI) of the sciatic nerve in small DRG neurons. Whole

Zhi-Jiang Huang; Xue-Jun Song



Dorsal root section elicits signs of neuropathic pain rather than reversing them in rats with L5 spinal nerve injury  

Microsoft Academic Search

Mechanical allodynia- and hyperalgesia-like behavior which develops in rats after L5 spinal nerve lesion has been suggested to be due to ectopic activity in the lesioned afferent neurons originating at the lesion site and\\/or in the dorsal root ganglion because it is eliminated by section of the dorsal root. Here we reevaluated the effect of a dorsal rhizotomy in rats

Sebastian Eschenfelder; Heinz-Joachim Häbler; Wilfrid Jänig



Detection of Residual Disc Hernia Material and Confirmation of Nerve Root Decompression at Lumbar Disc Herniation Surgery by Intraoperative Ultrasound  

Microsoft Academic Search

The aim of lumbar disc herniation surgery is the removal of herniated disc material (HDM) and complete decompression of the nerve root. As some patients present with residual HDM, we examined the ability of intraoperative ultrasound (IOUS) to detect this material. Between February 2006 and June 2007, we used IOUS in 30 patients undergoing surgery for lumbar disc herniation. They

Takeshi Aoyama; Kazutoshi Hida; Minoru Akino; Shunsuke Yano; Yoshinobu Iwasaki



Progress of myelination in the human fetal spinal nerve roots, spinal cord and brainstem with myelin basic protein immunohistochemistry  

Microsoft Academic Search

The early progress of myelination was studied, by means of myelin basic protein (MBP) immunohistochemistry and luxol-fast-blue (LFB) staining, in the spinal cord, spinal nerve roots and brainstem of 66 fetuses and neonates. The degree of myelination was classified from 1 (slight) to 4 (mature). MBP immunoreactivity exhibited slight LFB positivity. Myelination first occurred in the medial longitudinal fasciculus at

Soichiro Tanaka; Takashi Mito; Sachio Takashima



Movements elicited by electrical stimulation of muscles, nerves, intermediate spinal cord, and spinal roots in anesthetized and decerebrate cats  

Microsoft Academic Search

Electrical stimulation offers the possibility of restoring motor function of paralyzed limbs after spinal-cord injury or stroke, but few data are available to compare possible sites of stimulation, such as muscle, nerve, spinal roots, or spinal cord. The aim of this study was to establish some characteristics of stimulation at these sites in the anesthetized and midcollicular decerebrate cat. The

Yoichiro Aoyagi; Vivian K. Mushahwar; Richard B. Stein; Arthur Prochazka



Volumetric magnetic resonance imaging of dorsal root ganglia for the objective quantitative assessment of neuron death after peripheral nerve injury  

Microsoft Academic Search

Prevention of neuron death after peripheral nerve injury is vital to regaining adequate cutaneous innervation density and quality of sensation, and while experimentally proven neuroprotective therapies exist, there lacks suitable clinical outcome measures for translational research. Axotomized dorsal root ganglia (DRG) histologically exhibit volume reduction in proportion to the amount of neuronal death within them. Hence, this study evaluated the

Christian A. West; Karen A. Davies; Andrew M. Hart; Mikael Wiberg; Steve R. Williams; Giorgio Terenghi




PubMed Central

In dorsal root ganglia and peripheral nerve of the rat and other species, nucleoside phosphatase and unspecific cholinesterase reaction products are found in the plasma membranes and spaces between them at two sites: (1) Schwann cell-axon interfaces and mesaxons of unmyelinated fibers, and (2) sheath cell-perikaryon interfaces and interfaces between adjacent sheath cells. Acetylcholinesterase reaction product is found in the perikaryon (within the endoplasmic reticulum) and the axon (axoplasmic surface). Nucleoside phosphatase reaction product is also found in the numerous vacuoles at the surface of perineurium cells, ganglion sheath cells, and cells surrounding some ganglion blood vessels. Nucleoside phosphatase activities in the sections fail to respond, in the manner described for "transport ATPase," to diisopropylphosphofluoridate, sodium and potassium ions, and ouabain. Nucleoside diphosphates are hydrolyzed more slowly than triphosphates in unmyelinated fibers, and are not hydrolyzed at the perikaryon surface. Nucleoside monophosphates are either not hydrolyzed or hydrolyzed very slowly. In contrast to these localizations, which are believed to demonstrate sites of enzyme activity, it is considered likely that diffusion artifacts account for the nucleoside phosphatase reaction product frequently found along the outer surfaces of myelinated fibers and within vacuoles at the Schwann cell surfaces of these fibers. The diffuse reaction product seen in basement membranes of ganglion and nerve may also be artifact.

Novikoff, Alex B.; Quintana, Nelson; Villaverde, Humberto; Forschirm, Regina



Spinal nerve injury causes upregulation of ErbB2 and ErbB3 receptors in rat dorsal root ganglia  

PubMed Central

It is generally known that peripheral nerve injury causes changes in expression of some growth factors in the dorsal root ganglion. Altered expression of ErbB receptors, a well-known growth factor in somatic cells, reportedly follows peripheral nerve injury in the spinal dorsal horn; however, it remains unknown whether the expression of these receptors is altered in the dorsal root ganglion after nerve injury. Therefore, this study examined the gene expression profiles of ErbB receptors in bilateral lumbar (L)4/L5 dorsal root ganglia, using L5-selective spinal nerve ligation in model rats as a peripheral nerve injury model. The expression of ErbB2 and ErbB3 was observed in the dorsal root ganglia of the mature rat, despite ErbB1 and ErbB4 showing only subtle expression. We also demonstrated that peripheral nerve injury induced significant increases in ErbB2 and ErbB3 in the ipsilateral dorsal root ganglion as compared with uninjured nerve. Expression changes in ErbB receptors appear to play important roles in nerve injury and subsequent nerve regeneration.

Mizobuchi, Satoshi; Kanzaki, Hirotaka; Omiya, Hiroki; Matsuoka, Yoshikazu; Obata, Norihiko; Kaku, Ryuji; Nakajima, Hirochika; Ouchida, Mamoru; Morita, Kiyoshi



Nerve growth factor-mediated expression of galectin-3 in mouse dorsal root ganglion neurons.  


Galectin-3, a member of the galectin family of beta-galactoside-specific lectins has been found to be expressed by subsets of dorsal root ganglion (DRG) neurons during development and in adulthood. Here we show that (i) after 3-7 days in vitro, DRG neurons derived from neonatal mice express galectin-3 intra- and extracellularly and (ii) lectin expression requires the presence of nerve growth factor (NGF). After 3 days in vitro, a higher number of DRG neurons expressed galectin-3 in the presence of NGF (65 +/- 7%) than in the presence of brain-derived neurotrophic factor (BDNF, 30 +/- 3%) or neurotrophin-3 (NT-3, 34 +/- 3%). After 7 days in vitro, these numbers dropped to 51 +/- 3% (for NGF), 0% (for BDNF) and 8 +/- 4% (for NT-3), respectively. Our findings provide first evidence for the contribution of a neurotrophin to the neuronal expression of galectins and suggest an NGF/TrkA-mediated expression of galectin-3 by early postnatal DRG neurons. PMID:11065132

Pesheva, P; Kuklinski, S; Biersack, H J; Probstmeier, R



Progesterone produces antinociceptive and neuroprotective effects in rats with microinjected lysophosphatidic acid in the trigeminal nerve root  

PubMed Central

Background In our present study, we studied the role of demyelination of the trigeminal nerve root in the development of prolonged nociceptive behavior in the trigeminal territory. Results Under anesthesia, the Sprague-Dawley rats were mounted onto a stereotaxic frame and 3 ?L of lysophosphatidic acid (LPA, 1 nmol) was injected into the trigeminal nerve root to produce demyelination. This treatment decreased the air-puff thresholds, persisted until postoperative day 130, and then returned to the preoperative levels 160 days after LPA injection. The LPA-treated rats also showed a significant hyper-responsiveness to pin-prick stimulation. We further investigated the antinociceptive and neuroprotective effects of progesterone in rats undergoing demyelination of the trigeminal nerve root. Progesterone (8, 16 mg/kg/day) was administered subcutaneously, beginning on the operative day, for five consecutive days in the LPA-treated rats. Treatment with progesterone produced significant early anti-allodynic effects and delayed prolonged anti-allodynic effects. The expression of protein zero (P0) and peripheral myelin protein 22 (PMP22) were significantly down-regulated in the trigeminal nerve root on postoperative day 5 following LPA injection. This down-regulation of the P0 and PMP22 levels was blocked by progesterone treatment. Conclusions These results suggest that progesterone produces antinociceptive effects through neuroprotective action in animals with LPA-induced trigeminal neuropathic pain. Moreover, progesterone has potential utility as a novel therapy for trigeminal neuropathic pain relief at an appropriate managed dose and is therefore a possible future treatment strategy for improving the recovery from injury.



Accidental finding of an anomalous spinal nerve root during lumbar-disc surgery: a case report and a review of literature.  


Anomalies of lumbosacral nerve roots, even though are rare, have been well documented so far in the medical literature. The early diagnosis of these anomalies may be difficult and it is crucial to develop specific methods for depicting them. Preoperative diagnosis of anomalous lumbosacral spinal nerve roots using the magnetic resonance imaging is essential to facilitate thorough surgical planning in order to avoid unnecessary complications for the patient during surgery. The operative management of these anomalies depends on the patient's neurological problems and while asymptomatic and accidentally diagnosed cases do not require treatment, patients who suffer low back or sciatic pain need surgical intervention in order to decompress nerve roots. We report a 45-years old woman presented with severe low back pain associated with left lumboischialgia. Intraoperative finding of an aberrant L5/S1 nerve root, optimal surgical therapy and different classifications are discussed together with a review of literature. PMID:20977111

Houra, Karlo; Beros, Vili; Kovac, Damir; Sajko, Tomislav; Gnjidi?, Zivko; Rotim, Krehimir



MRI-guided periradicular nerve root infiltration therapy in low-field (0.23-T) MRI system using optical instrument tracking.  


The purpose of this study was to evaluate the feasibility of the MRI-guided periradicular nerve root infiltration therapy. Sixty-seven nerve root infiltrations under MRI guidance were done for 61 patients suffering from lumbosacral radicular pain. Informed consent was acquired from all patients. A 0.23-T open-MRI scanner with interventional tools (Outlook Proview, Philips Medical Systems, MR Technologies, Finland) was used. A surface coil was used in all cases. Nerve root infiltration was performed with MRI-compatible 20-G needle (Chiba type MReye, Cook, Bloomington, Ind.; or Manan type, MD Tech, Florida). The evaluation of clinical outcome was achieved with 6 months of clinical follow-up and questionnaire. The effect of nerve root infiltration to the radicular pain was graded: 1=good to excellent, i.e., no pain or not disturbing pain allowing normal physical activity at 3 months from the procedure; 2=temporary, i.e., temporary relief of pain; 3=no relief of pain; and 4=worsening of pain. As an adjunct to MRI-guided positioning of the needle the correct needle localization by the nerve root was confirmed with saline injection to nerve root channel and single-shot fast spin echo (SSFSE) imaging. The MRI guidance allowed adequate needle positioning in all but 1 case (98.5%). This failure was caused by degeneration-induced changes in anatomy. Of patients, 51.5% had good to excellent effect with regard to radicular pain from the procedure, 22.7% had temporary relief, 21.2% had no effect, and in 4.5% the pain worsened. Our results show that MRI guidance is accurate and safe in performing nerve root infiltration at lumbosacral area. The results of radicular pain relief from nerve root infiltration are comparable to CT or fluoroscopy studies on the subject. PMID:12042935

Sequeiros, Roberto Blanco; Ojala, Risto O; Klemola, Rauli; Vaara, Teuvo J; Jyrkinen, Lasse; Tervonen, Osmo A



Transverse Process and Needles of Medial Branch Block to Facet Joint as Landmarks for Ultrasound-Guided Selective Nerve Root Block  

PubMed Central

Background Selective lumbar nerve root block (SNRB) is generally accepted as an effective treatment method for back pain with sciatica. However, it requires devices producing radioactive materials such as C-arm fluoroscopy. This study evaluated the usefulness of the longitudinal view of transverse process and needles for medial branch block as landmarks under ultrasonography. Methods We performed selective nerve root block for 96 nerve roots in 61 patients under the guidance of ultrasound. A curved probe was used to identify the facet joints and transverse processes. Identifying the lumbar nerve roots under the skin surface and ultrasound landmarks, the cephalad and caudal medial branch blocks were undertaken under the transverse view of sonogram first. A needle for nerve root block was inserted between the two transverse processes under longitudinal view, while estimating the depth with the needle for medial branch block. We then injected 1.0 mL of contrast medium and checked the distribution of the nerve root with C-arm fluoroscopy to evaluate the accuracy. The visual analog scale (VAS) was used to access the clinical results. Results Seven SNRBs were performed for the L2 nerve root, 15 for L3, 49 for L4, and 25 for L5, respectively. Eighty-six SNRBs (89.5%) showed successful positioning of the needles. We failed in the following cases: 1 case for the L2 nerve root; 2 for L3; 3 for L4; and 4 for L5. The failed needles were positioned at wrong leveled segments in 4 cases and inappropriate place in 6 cases. VAS was improved from 7.6 ± 0.6 to 3.5 ± 1.3 after the procedure. Conclusions For SNRB in lumbar spine, the transverse processes under longitudinal view as the ultrasound landmark and the needles of medial branch block to the facet joint can be a promising guidance.

Kim, Daehee; Choi, Donghyuk; Kim, Chungyoung; Kim, Jeongseok



Computed Tomography Fluoroscopy-Guided Selective Nerve Root Block for Acute Cervical Disc Herniation  

PubMed Central

Objective To analyze the clinical outcomes of computed tomography (CT) fluoroscopy-guided selective nerve root block (SNRB) for severe arm pain caused by acute cervical disc herniation. Methods The authors analyzed the data obtained from 25 consecutive patients who underwent CT fluoroscopy-guided SNRB for severe arm pain, i.e., a visual analogue scale (VAS) score of 8 points or more, caused by acute soft cervical disc herniation. Patients with chronic arm pain, motor weakness, and/or hard disc herniation were excluded. Results The series comprised 19 men and 6 women whose mean age was 48.1 years (range 35-72 years). The mean symptom duration was 17.5 days (range 4-56 days) and the treated level was at C5-6 in 13 patients, C6-7 in 9, and both C5-6 and C6-7 in 3. Twenty-three patients underwent SNRB in 1 session and 2 underwent the procedure in 2 sessions. No complications related to the procedures occurred. At a mean follow-up duration of 11.5 months (range 6-22 months), the mean VAS score and NDI significantly improved from 9 and 58.2 to 3.4 and 28.1, respectively. Eighteen out of 25 patients (72%) showed successful clinical results. Seven patients (28%) did not improve after the procedure, and 5 of these 7 underwent subsequent anterior cervical discectomy and fusion. Conclusion CT fluoroscopy-guided SNRB may play a role as a primary conservative treatment for severe arm pain caused by acute cervical disc herniation.

Eun, Sang Soo; Chang, Won Sok; Bae, Sang Jin; Lee, Sang-Ho



Blood-nerve barrier: distribution of anionic sites on the endothelial plasma membrane and basal lamina of dorsal root ganglia.  


Previous investigations of the blood-nerve barrier have correlated the greater permeability of ganglionic endoneurial vessels, compared to those of nerve trunks, with the presence of fenestrations and open intercellular junctions. Recent studies have demonstrated reduced endothelial cell surface charge in blood vessels showing greater permeability. To determine the distribution of anionic sites on the plasma membranes and basal laminae of endothelial cells in dorsal root ganglia, cationic colloidal gold and cationic ferritin were used. Electron microscopy revealed the existence of endothelial microdomains with differing labelling densities. Labelling indicated that caveolar and fenestral diaphragms and basal laminae are highly anionic at physiological pH, luminal plasma membranes and endothelial processes are moderately charged and abluminal plasma membranes are weakly anionic. Tracers did not occur in caveolae or cytoplasmic vesicles. In vitro tracer experiments at pH values of 7.3, 5.0, 3.5 and 2.0 indicated that the anionic charge on the various endothelial domains was contributed by chemical groups with differing pKa values. In summary, the labelling of ganglionic and sciatic nerve vessels was similar except for the heavy labelling of diaphragms in a minority of endoneurial vessels in ganglia. This difference is likely to account in part for the greater permeability of ganglionic endoneurial vessels. The results are discussed with regard to the blood-nerve and -brain barriers and vascular permeability in other tissues and a comparison made between the ultrastructure and anionic microdomains of epi-, peri- and endoneurial vessels of dorsal root ganglia and sciatic nerves. PMID:1960538

Bush, M S; Reid, A R; Allt, G



Arteriovenous fistula in a nerve root of the cauda equina fed by a proximal radiculo-medullary artery: a report of two cases.  


While there have been a few reports on cases of intradural spinal arteriovenous fistula located on the filum terminale, no cases of its location in a nerve root of the cauda equina have been reported to date.We describe two such cases and describe the intraoperative findings. A 40-year-old man presented weakness of his left leg. Another 62-year-old man presented paraparesis dominantly in his left leg with urinary hesitation. In both cases, spinal T2-weighted magnetic resonance images showed edema of the spinal cord, indicating a flow void around it. Digital subtraction angiography disclosed an anterior radicular artery branching from the anterior spinal artery on the surface of the conus medullaris and a turnaround vein running in the opposite direction within the cauda equina. In the first patient, while the feeding artery running along a nerve root was detected, the draining vein and the fistula were not identified at first sight. An incision into the respective nerve root exposed their location within it. In the second patient, unlike the first case, the feeding artery and the fistula were buried in a nerve root, while the draining vein was running along the nerve's surface. In both cases, permanent clips were applied to the draining vein closest to the fistula. The recognition of a hidden fistulous point in a nerve root of the cauda equina is essential for successful obliteration of the fistula. PMID:21696662

Ohtonari, T; Ota, S; Nishihara, N; Suwa, K; Ota, T; Sekihara, Y; Tanaka, A; Koyama, T



Spatio-temporal pattern of induction of bradykinin receptors and inflammation in rat dorsal root ganglia after unilateral nerve ligation.  


Expression of bradykinin receptors was analyzed in freshly isolated dorsal root ganglion neurons of the ipsi- and contralateral segments L4/L5, L2/L3, and T12/T13 two to twenty days after unilateral injury of the adult rat sciatic nerve using gold labeled bradykinin. The number of infiltrating leucocytes was investigated by flow cytometry. Sciatic nerve injury transiently increased the proportion of neurons expressing bradykinin receptors not only in the ipsilateral ganglia L4/L5, but also in the homonymous contralateral ganglia and also bilaterally in the adjacent ganglia L2/L3. Neurons of the ganglia T12/T13 were not affected. The time course of upregulation was different between neurons of the injured nerve and uninjured ones. Furthermore, the proportion of neurons expressing a high density of receptors increased also bilaterally in ganglia L4/L5 and L2/L3. As on the ipsilateral side, the increase in neurons expressing bradykinin receptors in the contralateral homonymous ganglia was due to an induction of the B1 receptor subtype and an upregulation of the B2 subtype. As a possible source for stimulating factors for induction of bradykinin receptors the number of macrophages and lymphocytes was investigated two to twenty days after nerve ligation. No increase was observed prior to day ten and only in ipsilateral ganglia L4/L5, not contralaterally and not in adjacent ganglia L2/L3 and T12/T13. The experiments show that the induction of bradykinin receptors following a unilateral nerve lesion is not restricted to neurons projecting into the damaged nerve but is (i) bilateral, (ii) different in time course between injured and uninjured neurons, and (iii) locally confined to neurons of the adjacent ganglia. Macrophages and lymphocytes are increased after ten day ligation only in the affected ganglia and are probably not involved in the induction of bradykinin receptors. PMID:10568857

Eckert, A; Segond von Banchet, G; Sopper, S; Petersen, M



microRNA-222 Targeting PTEN Promotes Neurite Outgrowth from Adult Dorsal Root Ganglion Neurons following Sciatic Nerve Transection  

PubMed Central

Dorsal root ganglia (DRG) neurons spontaneously undergo neurite growth after nerve injury. MicroRNAs (miRNAs), as small, non-coding RNAs, negatively regulate gene expression in a variety of biological processes. The roles of miRNAs in the regulation of responses of DRG neurons to injury stimuli, however, are not fully understood. Here, microarray analysis was performed to profile the miRNAs in L4-L6 DRGs following rat sciatic nerve transection. The 26 known miRNAs were differentially expressed at 0, 1, 4, 7, 14 d post injury, and the potential targets of the miRNAs were involved in nerve regeneration, as analyzed by bioinformatics. Among the 26 miRNAs, microRNA-222 (miR-222) was our research focus because its increased expression promoted neurite outgrowth while it silencing by miR-222 inhibitor reduced neurite outgrowth. Knockdown experiments confirmed that phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a major inhibitor of nerve regeneration, was a direct target of miR-222 in DRG neurons. In addition, we found that miR-222 might regulate the phosphorylation of cAMP response element binding protein (CREB) through PTEN, and c-Jun activation might enhance the miR-222 expression. Collectively, our data suggest that miR-222 could regulate neurite outgrowth from DRG neurons by targeting PTEN.

Wang, Yongjun; Gong, Leilei; Tang, Xiaoyan; Yu, Bin; Gu, Xiaosong; Ding, Fei



MRI of the cervical nerve roots in the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy: a single-institution, retrospective case-control study  

PubMed Central

Objective To systematically evaluate the usefulness of assessing the cervical nerve roots by MRI for the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Design Single-institution, retrospective case–control study. Setting A regional referral hospital. Participants We retrospectively enrolled 15 consecutive patients with CIDP who satisfied the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) typical and definite criteria and underwent cervical MRI. 30 control patients who had also undergone cervical MRI were included, matched with regard to sex, age and MRI system. The diagnoses of the control patients included cervical spondylosis (n=19), cervical spine trauma (n=2), infection (n=1), malignancies (n=4), demyelinating disorders (n=2) and neurodegenerative disorders (n=2). Measurement A radiologist determined the C5–C8 root diameters on the coronal short tau inversion recovery (STIR) images. Signal intensities of these roots were quantified as nerve-to-muscle contrast-to-noise ratios (CNRs), which were calculated using mean signal intensities of the roots and sternocleidomastoid muscle as well as SD of background noise. Statistical analyses were performed to determine the diagnostic accuracy of the diameters and nerve-to-muscle CNRs. Another radiologist reviewed MRI for ensuring reproducibility. Results The root diameters showed no significant differences between the patients with CIDP and control patients. The nerve-to-muscle CNRs were significantly higher in the patients with CIDP. We defined the sum of nerve-to-muscle CNRs of C5–C8 roots as the CNR score to serve as an index of overall signal intensity. The area under the receiver operating characteristic curve of CNR scores was 0.731. The reproducibility of the assessment procedure was satisfactory. Conclusions Our results suggest that assessment of the cervical nerve roots by MRI is useful for CIDP diagnosis when the signal intensities, rather than the diameters, are paid more attention on STIR images.

Tanaka, Kanta; Mori, Nobuyuki; Yokota, Yusuke; Suenaga, Toshihiko



Transient quadriplegia after fluoroscopic-guided selective cervical nerve root block in a patient who received cervical interbody fusion -A case report-.  


Selective cervical nerve root block is executed for patients who have symptoms of cervical radiculopathy for diagnostic and therapeutic purposes. However several catastrophic complications caused by this procedure have been reported including neurological complications. A 43-year-old male received a C5 selective cervical nerve root block procedure due to continuous radiating pain even after cervical discectomy and interbody fusion was performed. At the time of the procedure, the contrast outline revealed reflux of the nerve root and epidural space. But after the procedure was performed, the patient experienced decreased sensation in the upper and low extremities as well as motor paralysis of both extremities. Our sspecting diagnosis was anterior spinal artery syndrome but both sensory and motor functions were subsequently recovered within a few hours after the procedure was completed. Due to the difficult nature of this case, we reported these complications and reviewed current literature related to this study. PMID:21286472

Lee, Mi Hyeon; Cha, Young Deog; Song, Jang Ho; An, Young Mi; Han, Jeong Uk; Lee, Du Ik



Transient quadriplegia after fluoroscopic-guided selective cervical nerve root block in a patient who received cervical interbody fusion -A case report-  

PubMed Central

Selective cervical nerve root block is executed for patients who have symptoms of cervical radiculopathy for diagnostic and therapeutic purposes. However several catastrophic complications caused by this procedure have been reported including neurological complications. A 43-year-old male received a C5 selective cervical nerve root block procedure due to continuous radiating pain even after cervical discectomy and interbody fusion was performed. At the time of the procedure, the contrast outline revealed reflux of the nerve root and epidural space. But after the procedure was performed, the patient experienced decreased sensation in the upper and low extremities as well as motor paralysis of both extremities. Our sspecting diagnosis was anterior spinal artery syndrome but both sensory and motor functions were subsequently recovered within a few hours after the procedure was completed. Due to the difficult nature of this case, we reported these complications and reviewed current literature related to this study.

Lee, Mi Hyeon; Song, Jang Ho; An, Young Mi; Han, Jeong Uk; Lee, Du Ik



Changes in lectin binding of lumbar dorsal root ganglia neurons and peripheral axons after sciatic and spinal nerve injury in the rat  

Microsoft Academic Search

The effects of chronic lesions of rat lumbar spinal or sciatic nerves on the binding of Glycine max (soybean) agglutinin to galacto-conjugates, in small-and medium-size primary sensory neurons of the L4 and L5 dorsal root ganglia, were examined over a 580-day period. Spinal nerve section resulted in a marked decrease in the population of stained neurons within 7 days. However,

Jean-Marie Peyronnard; Louise Charron; Jean-Pierre Messier; Jeanne Lavoie; Christian Leger; Feliciana Faraco-Cantin



A literature review reveals that trials evaluating treatment of non-specific low back pain use inconsistent criteria to identify serious pathologies and nerve root involvement  

PubMed Central

Objectives The broad aim of this study was to assess the homogeneity of patients included in trials of non-specific low back pain (NSLBP). To do this, we investigated the consistency and clarity of criteria used to identify and exclude participants with serious pathologies and nerve root compromise in randomized controlled trials, investigating interventions for NSLBP. Methods We searched Medline database for randomized controlled trials of low back pain (LBP). published between 2000 and 2009. We then randomly selected and screened trials for inclusion until we had 50 eligible trials. Data were extracted on the criteria used to identify cases of serious conditions (e.g. cancer, fracture) and nerve root involvement. Results The majority of papers (35/50) explicitly excluded patients with serious pathology. However, the terminology used and examples given were highly variable. Nerve root involvement was an exclusion criterion in the majority but not all studies. The criteria used for excluding patients with nerve root involvement varied greatly between studies. The most common criteria were ‘motor, sensory or reflex changes’ (nine studies), followed by ‘pain radiating below the knee’ (five studies) and ‘reduced straight leg raise which reproduces leg pain’ (five studies). In half of the included studies, the criteria used, while alluding to nerve root involvement, were not explained adequately for us to determine the types of patients included or excluded. Discussion The inconsistent and unclear criteria used to identify cases of serious pathology and nerve root compromise means that published trials of LBP likely include heterogeneous patient populations. This trait limits our ability to make comparisons across trials or pool studies. Standardization and consensus is important for future research.

Williams, Ciaran; Hancock, Mark J; Ferreira, Manuela; Ferreira, Paulo; Maher, Chris G



Chemical and mechanical nerve root insults induce differential behavioral sensitivity and glial activation that are enhanced in combination  

PubMed Central

Both chemical irritation and mechanical compression affect radicular pain from disc herniation. However, relative effects of these insults on pain symptoms are unclear. This study investigated chemical and mechanical contributions for painful cervical nerve root injury. Accordingly, the C7 nerve root separately underwent chromic gut exposure, 10gf compression, or their combination. Mechanical allodynia was assessed, and glial reactivity in the C7 spinal cord tissue was assayed at days 1 and 7 by immunohistochemistry using GFAP and OX-42 as markers of astrocytes and microglia, respectively. Both chromic gut irritation and 10gf compression produced ipsilateral increases in allodynia over sham (p<0.048); combining the two insults significantly (p<0.027) increased ipsilateral allodynia compared to either insult alone. Behavioral hypersensitivity was also produced in the contralateral forepaw for all injuries, but only the combined insult was significantly increased over sham (p<0.031). Astrocytic activation was significantly increased over normal (p<0.001) in the ipsilateral dorsal horn at one day after either compression or the combined injury. By day 7, GFAP-reactivity was further increased for the combined injury compared to day 1 (p<0.001). In contrast, spinal OX-42 staining was generally variable, with only mild activation at day 1. By day 7 after the combined injury, there were significant (p<0.003) bilateral increases in OX-42 staining over normal. Spinal astrocytic and microglial reactivity follow different patterns after chemical root irritation, compression, and a combined insult. The combination of transient compression and chemical irritation produces sustained bilateral hypersensitivity, sustained ipsilateral spinal astrocytic activation and late onset bilateral spinal microglial activation.

Rothman, Sarah M.; Winkelstein, Beth A.



Intracisternal administration of NR2 subunit antagonists attenuates the nociceptive behavior and p-p38 MAPK expression produced by compression of the trigeminal nerve root  

PubMed Central

Background We investigated the role of the central NMDA receptor NR2 subunits in the modulation of nociceptive behavior and p-p38 MAPK expression in a rat model with compression of the trigeminal nerve root. To address this possibility, changes in air-puff thresholds and pin-prick scores were determined following an intracisternal administration of NR2 subunit antagonists. We also examined effects of NR2 subunit antagonists on the p-p38 MAPK expression. Results Experiments were carried out using male Sprague-Dawley rats weighing (200-230 g). Compression of the trigeminal nerve root was performed under pentobarbital sodium (40 mg/kg) anesthesia. Compression of the trigeminal nerve root produced distinct nociceptive behavior such as mechanical allodynia and hyperalgesia. Intracisternal administration of 10 or 20 ?g of D-AP5 significantly increased the air-puff threshold and decreased the pin-prick scores in a dose-dependent manner. The intracisternal administration of PPPA (1, 10 ?g), or PPDA (5, 10 ?g) increased the air-puff threshold and decreased the pin-prick scores ipsilateral as well as contralateral to the compression of the trigeminal root. Compression of the trigeminal nerve root upregulated the expression of p-p38 MAPK in the ipsilateral medullary dorsal horn which was diminished by D-AP5, PPPA, PPDA, but not Ro25-6981. Conclusions Our findings suggest that central NMDA receptor NR2 subunits play an important role in the central processing of trigeminal neuralgia-like nociception in rats with compression of the trigeminal nerve root. Our data further indicate that the targeted blockade of NR2 subunits is a potentially important new treatments strategy for trigeminal neuralgia-like nociception.



Percutaneous sacral third nerve root neurostimulation improves symptoms and normalizes urinary HB-EGF levels and antiproliferative activity in patients with interstitial cystitis  

Microsoft Academic Search

Objectives. A highly effective treatment for interstitial cystitis (IC) remains elusive. We determined whether sacral third nerve root (S3) percutaneous neurostimulation (PNS) might be effective in relieving symptoms of IC, as well as in normalizing urinary factors that are specifically altered in IC.Methods. Six consecutive patients with symptoms and cystoscopic findings compatible with IC underwent 5 days of continuous S3

Toby C Chai; Chen-Ou Zhang; John W Warren; Susan Keay



Comparison of neuropathic pain induced by the application of normal and mechanically compressed nucleus pulposus to lumbar nerve roots in the rat  

Microsoft Academic Search

We studied whether applying nucleus pulposus tissue, obtained from tail intervertebral discs that had been subjected to chronic mechanical compression, to the lumbar nerve roots produces hyperalgesia, which is thought to be a pain-related behavior in the rat. An Ilizarov-type apparatus was used for immobilization and chronically applied compression of the rat tail for eight weeks. Three weeks after application

Mamoru Kawakami; Hiroshi Hashizume; Hideto Nishi; Takuji Matsumoto; Tetsuya Tamaki; Koichi Kuribayashi



Lumbar 5 ventral root transection-induced upregulation of nerve growth factor in sensory neurons and their target tissues: a mechanism in neuropathic pain  

Microsoft Academic Search

We have previously demonstrated that profound and persistent neuropathic pain as displayed by mechanical and cold allodynia and thermal hyperalgesia can be produced by a lumbar 5 ventral root transection (L5 VRT) model in adult rats in which only the motor nerve fibers were injured without axotomy of sensory neurons. However, the underlying mechanisms remain to be determined. In this

Li Li; Cory J Xian; Jin-Hua Zhong; Xin-Fu Zhou



Replicate high-density rat genome oligonucleotide microarrays reveal hundreds of regulated genes in the dorsal root ganglion after peripheral nerve injury  

Microsoft Academic Search

BACKGROUND: Rat oligonucleotide microarrays were used to detect changes in gene expression in the dorsal root ganglion (DRG) 3 days following sciatic nerve transection (axotomy). Two comparisons were made using two sets of triplicate microarrays, naïve versus naïve and naïve versus axotomy. RESULTS: Microarray variability was assessed using the naïve versus naïve comparison. These results support use of a P

Michael Costigan; Katia Befort; Laurie Karchewski; Robert S Griffin; Donatella D'Urso; Andrew Allchorne; Joanne Sitarski; James W Mannion; Richard E Pratt; Clifford J Woolf



Utility of Limited Protocol Magnetic Resonance Imaging Lumbar Spine for Nerve Root Compression in a Developing Country, Is It Accurate and Cost Effective?  

PubMed Central

Study Design Cross sectional study. Purpose To determine the accuracy of the screening magnetic resonance study of the lumbar spine in the diagnosis of nerve root compression in cases of low back pain as compared to the routine magnetic resonance imaging (MRI) study of the lumbar spine. Overview of Literature No local study has been conducted for this purpose. In an international study, the reported sensitivity and specificity of screening MRI lumbar spine protocol in the detection of nerve root compression are 54% and 100% respectively. Methods Patients of both genders older than 20 years of age with low back pain of any duration or any severity who were referred to the radiology department of Aga Khan University Hospital for MRI of their lumbar spine were evaluated. Two sets of MRI imaging were recruited for each patient: one labeled as 'screening' and the other labeled as 'routine'. The findings of screening MRI were compared with the findings of the routine MRI study. Results A total of 109 patients fulfilling the inclusion criteria were included in this study. The diagnostic accuracy, specificity and sensitivity of the screening protocol in our study was 100%, 100% and 100%, respectively in comparison with the routine MRI lumbar spine study for the detection of nerve root compression. Conclusions Our data proved that the MRI screening study is a highly accurate tool, and its findings are comparable to the routine study for the detection of nerve root compression especially in cases of lumbar spondylosis.

Hilal, Kiran; Sajjad, Zafar; Khan, Dawar



Dermatomal somatosensory evoked potential demonstration of nerve root decompression after VAX-D therapy  

Microsoft Academic Search

Reductions in low back pain and referred leg pain associated with a diagnosis of herniated disc, degenerative disc disease or facet syndrome have previously been reported after treatment with a VAX-D table, which intermittently distracts the spine. The object of this study was to use dermatomal somatosensory evoked potentials (DSSEPs) to demonstrate lumbar root decompression following VAX-D therapy. Seven consecutive

William K. Naguszewski; Robert K. Naguszewski; Earl E. Gose



Translaminar Microendoscopic Herniotomy for Cranially Migrated Lumbar Disc Herniations Encroaching on the Exiting Nerve Root in the Preforaminal and Foraminal Zones  

PubMed Central

Study Design Case series. Purpose The aim of this study was to describe translaminar microendoscopic herniotomy (TL-MEH) for cranially migrated lumbar disc herniations encroaching on the exiting nerve root in the preforaminal and foraminal zones and to report preliminary results of the procedure. Overview of Literature Conventional interlaminar approaches for preforaminal and foraminal lumbar disc herniations result in extensive removal of the lamina and facet joint to remove disc fragments safely. More destructive approaches increase the risk of postoperative segmental instability. Methods TL-MEH is a minimally invasive procedure for herniotomy via the translaminar approach using a microendoscopic technique. TL-MEH was performed in seven patients with a cranially migrated lumbar disc herniation encroaching on the exiting nerve root. The disc fragments were located in the preforaminal zone in four patients, and in the preforaminal and foraminal zones in three. Results All patients experienced immediate relief from symptoms after surgery and satisfactory results at the final follow-up. Surgical complications, such as a dural tear, nerve injury, and surgical site infection, were not investigated. Conclusions TL-MEH seemed to be an effective and safe alternative minimally invasive surgical option for patients with a cranially migrated lumbar disc herniation encroaching the exiting nerve root in the preforaminal and foraminal zones.

Tono, Osamu; Senba, Hideyuki; Kitamura, Takahiro; Komiya, Norihiro; Oga, Masayoshi; Shidahara, Satoshi



Intraobserver and interobserver reproducibility of the novel transcription method for selection of potential nerve root compression in MRI study in degenerative disease of the lumbar spine  

PubMed Central

Background Degenerative disease of the lumbar spine is characterized by symptoms related to the affected nerve root. A recently described method allows the classification of the roots in relation to the occurrence of compression on its course. This method can serve as a clinical selection tool and decision support for semi-invasive pain therapy in back pain patients. Material/Methods We examined 40 lumbar spine MRIs in 3 sessions of transcription each, according to the method being evaluated. Every MRI evaluation was performed by each of 3 different observers. Intra- and interobserver reproducibility was calculated using chance-corrected agreement using a weighted kappa (?) value with quadratic weights to assess reliability for each nerve root separately. Results We found high intraobserver agreement in indication of the root with most pronounced interference due to potential compression by degenerative changes, at the level mean ?=0.81 (with 95% CI, range 0.04). Less agreement was observed in the interobserver evaluation test with the mean ?=0.75 (95% CI within the range not exceeding 0.03), although it still reached the substantial agreement. Conclusions This zstudy provides evidence for substantial inter- and intraobserver agreement for the decision support method allowing selection of the most serious nerve structure compression in degenerative disease of the lumbar spine based on of the MRI description.

Kubaszewski, Lukasz; Nowakowski, Andrzej; Gasik, Robert; LabedY, Wojciech



Vascularization of the dorsal root ganglia and peripheral nerve of the mouse: Implications for chemical-induced peripheral sensory neuropathies  

PubMed Central

Although a variety of industrial chemicals, as well as several chemotherapeutic agents used to treat cancer or HIV, preferentially induce a peripheral sensory neuropathy what remains unclear is why these agents induce a sensory vs. a motor or mixed neuropathy. Previous studies have shown that the endothelial cells that vascularize the dorsal root ganglion (DRG), which houses the primary afferent sensory neurons, are unique in that they have large fenestrations and are permeable to a variety of low and high molecular weight agents. In the present report we used whole-mount preparations, immunohistochemistry, and confocal laser scanning microscopy to show that the cell body-rich area of the L4 mouse DRG has a 7 fold higher density of CD31+ capillaries than cell fiber rich area of the DRG or the distal or proximal aspect of the sciatic nerve. This dense vascularization, coupled with the high permeability of these capillaries, may synergistically contribute, and in part explain, why many potentially neurotoxic agents preferentially accumulate and injure cells within the DRG. Currently, cancer survivors and HIV patients constitute the largest and most rapidly expanding groups that have chemically induced peripheral sensory neuropathy. Understanding the unique aspects of the vascularization of the DRG and closing the endothelial fenestrations of the rich vascular bed of capillaries that vascularize the DRG before intravenous administration of anti-neoplastic or anti-HIV therapies, may offer a mechanism based approach to attenuate these chemically induced peripheral neuropathies in these patients.

Jimenez-Andrade, Juan M; Herrera, Monica B; Ghilardi, Joseph R; Vardanyan, Marina; Melemedjian, Ohannes K; Mantyh, Patrick W



Spatio-temporal changes of SDF1 and its CXCR4 receptor in the dorsal root ganglia following unilateral sciatic nerve injury as a model of neuropathic pain  

Microsoft Academic Search

There is a growing evidence that chemokines and their receptors play a role in inducing and maintaining neuropathic pain.\\u000a In the present study, unilateral chronic constriction injury (CCI) of rat sciatic nerve under aseptic conditions was used\\u000a to investigate changes for stromal derived factor-1 (SDF1) and its CXCR4 receptor in lumbal (L4–L5) and cervical (C7–C8) dorsal\\u000a root ganglia (DRG) from

Petr Dubový; I. Klusáková; I. Svíženská; V. Brázda



Pulsed Radiofrequency of the Dorsal Root Ganglia is Superior to Pharmacotherapy or Pulsed Radiofrequency of the Intercostal Nerves in the Treatment of Chronic Postsurgical Thoracic Pain  

Microsoft Academic Search

pulsed RF of the intercostal nerves (ICN) and pulsed RF of the dorsal root ganglia (DRG) in CPTP. Methods: Retrospective data analy- sis involving 49 patients. Results: At 6-week follow-up, 61.5% of the pulsed RF DRG group reported ? 50% pain relief vs. 27.3% in the medical management (MM) group and 21.4% in the ICN group (P=0.12). At 3-month follow-up,

Steven P. Cohen; Anthony Sireci; Christopher L. Wu; Thomas M. Larkin; Kayode A. Williams; Robert W. Hurley


Selective regulation of 3?-hydroxysteroid oxido-reductase expression in dorsal root ganglion neurons: A possible mechanism to cope with peripheral nerve injury-induced chronic pain  

Microsoft Academic Search

The enzyme 3?-hydroxysteroid oxido-reductase (3?-HSOR) catalyzes the synthesis and bioavailability of 3?,5?-neurosteroids as allopregnanolone (3?,5?-THP) which activates GABAA receptors and blocks T-type calcium channels involved in pain mechanisms. Here, we used a multidisciplinary approach to demonstrate that 3?-HSOR is a cellular target the modulation of which in dorsal root ganglia (DRG) may contribute to suppress pain resulting from peripheral nerve

Christine Patte-Mensah; Laurence Meyer; Véronique Schaeffer; Ayikoe G. Mensah-Nyagan



Rehabilitation Considerations of a Brachial Plexus Injury with Complete Avulsion of C5 and C6 Nerve Roots in a College Football Player  

PubMed Central

Severe brachial plexus injuries are rare in sports, but they have catastrophic results with a significant loss of function in the involved upper extremity. Nerve root avulsions must be timely managed with prompt evaluation, accurate diagnosis, and surgical treatment to optimize the potential for a functional outcome. This case report describes the mechanism of injury, diagnostic evolution, surgical management, and rehabilitation of a college football player who sustained a traumatic complete nerve root avulsion of C5 and C6 (upper trunk of the brachial plexus). Diagnostics included clinical evaluation, magnetic resonance imaging, computed tomography myelogram, and electromyogram. Surgical planning included nerve grafting and neurotization (nerve transfer). Rehabilitation goals were to bring the hand to the face (active biceps function), to stabilize the shoulder for abduction and flexion, and to reduce neuropathic pain. Direct current stimulation, bracing, therapeutic exercise, and biofeedback were used to maximize the use of the athlete’s upper extremity. Although the athlete could not return to sport or normal function by most standards, his results were satisfactory in that he regained an ability to perform many activities of daily living.

Saliba, Susan; Saliba, Ethan N.; Pugh, Kelli F.; Chhabra, Abhinav; Diduch, David



Different expression of tissue inhibitor of metalloproteinase family members in rat dorsal root ganglia and their changes after peripheral nerve injury.  


Matrix metalloproteinase 9 (MMP9) and MMP2 are important in the development and maintenance of neuropathic pain behavior induced by peripheral nerve injury. The enzymatic activity of MMP9 and MMP2 is balanced specifically by tissue inhibitor of metalloproteinase 1 (TIMP1) and TIMP2, respectively. In present study, we measured the effect of peripheral nerve injury on the expression of TIMP1 and TIMP2 in adult dorsal root ganglia (DRG). A dramatic increase of TIMP1 mRNA and a decrease of TIMP2 in DRG after sciatic nerve transection (SNT) were displayed through a real-time PCR method. Furthermore, data showed by in situ hybridization that TIMP1 mRNA was only localized in DRG satellite cells under normal conditions. TIMP1 mRNA was increased in satellite cells, and induced within sensory neurons after SNT. Analysis of neuronal profiles showed that induced TIMP1 mRNA was mainly contained in small and medium DRG neurons. Further study displayed that induced TIMP1 mRNA was predominantly present in activating transcription factor 3 (ATF3)-positive injured DRG neurons. Comparatively, TIMP2 mRNA was mostly contained within sensory neurons and the overall amount decreased at the late stage after nerve injury. These data showed different change of TIMPs in DRG after peripheral nerve injury. PMID:21782897

Huang, B; Zhao, X; Zheng, L-B; Zhang, L; Ni, B; Wang, Y-W



Impaired molecular regenerative responses in sensory neurones of diabetic rats: gene expression changes in dorsal root ganglia after sciatic nerve crush.  


This study investigated changes in gene expression in lumbar dorsal root ganglia (DRG), contralateral and ipsilateral to a sciatic nerve crush in control and streptozotocin (STZ)-induced diabetic rats. After 10 weeks of diabetes, the left sciatic nerves of all rats were crushed at mid-thigh level, and the rats were maintained for a further 2 weeks. Northern blots, with internal standards, were made from L4 and L5 (pooled) DRG on each side to compare RNA hybrids from ganglia attached to crushed nerves with those attached to intact nerves. The expression of growth-associated proteins, GAP-43 and Talpha1 alpha-tubulin mRNA in DRG, was stimulated (all P < 0.05) by crush injury in control and diabetic rats. Steady-state expression of transcripts for neurofilament (NF) proteins (NF-L, NF-H) and the high-affinity NGF receptor, trkA was decreased by diabetes in the contralateral ganglia to the crush (all P < 0.05). Crush injury further decreased expression of these transcripts in both control and diabetic rats (all P < 0.05). This reduced expression of mRNA coding for both growth-associated proteins, and neurofilament proteins in ganglia of diabetic rats could participate in the reduced competence of the regenerative response to nerve crush. PMID:9392496

Mohiuddin, L; Tomlinson, D R



Selective decrease of small sensory neurons in lumbar dorsal root ganglia labeled with horseradish peroxidase after ND:YAG laser irradiation of the tibial nerve in the rat  

SciTech Connect

Recent electrophysiological evidence indicates that Q-switched Nd:YAG laser irradiation might have selective effects on neural impulse transmission in small slow conducting sensory nerve fibers as compared to large diameter afferents. In an attempt to clarify the ultimate fate of sensory neurons after laser application to their peripheral axons, we have used horseradish peroxidase (HRP) as a cell marker to retrogradely label sensory neurons innervating the distal hindlimb in the rat. Pulsed Nd:YAG laser light was applied to the tibial nerve at pulse energies of 70 or 80 mJ/pulse for 5 min in experimental rats. Seven days later HRP was applied to the left (laser-treated) and to the contralateral (untreated) tibial nerve proximal to the site of laser irradiation. In control animals the numbers of HRP-labeled dorsal root ganglion cells were not significantly different between the right and the left side. In contrast, after previous laser irradiation labeling was always less on the laser-treated side (2183 +/- 513 cells, mean +/- SEM) as compared to the untreated side (3937 +/- 225). Analysis of the dimensions of labeled cells suggested that the reduction of labeled cells on the laser-treated side was mainly due to a deficit in small sensory neurons. Since the conduction velocity of nerve fibers is related to the size of their somata, our histological data imply that laser light selectively affects retrograde transport mechanisms for HRP in slow conducting sensory nerve fibers.

Wesselmann, U.; Lin, S.F.; Rymer, W.Z. (Northwestern Univ. Medical School, Chicago, IL (USA))



Aggrecan components differentially modulate nerve growth factor-responsive and neurotrophin-3-responsive dorsal root ganglion neurite growth.  


Aggrecan is one of the major chondroitin sulfate proteoglycans (CSPGs) expressed in the central nervous system. The signaling pathways activated downstream of cell interaction with aggrecan and with CSPGs in general and the importance of chondroitin sulfate-glycosaminoglycan side chains in their inhibition are unclear. Therefore, to analyze the effect of different components of aggrecan in inhibiting neurite growth, neurite outgrowth was quantified in an in vitro model in which chick dorsal root ganglion (DRG) explants were grown on substrates containing aggrecan bound to hyaluronan and link protein as a macromolecular aggregate, aggrecan monomers, hyaluronan, or ChABC-treated aggrecan. Aggrecan aggregate, aggrecan monomer, and hyaluronan inhibited neurite outgrowth from nerve growth factor (NGF)- and neurotrophin-3 (NT3)-responsive DRG neurons. Aggrecan inhibition was dependent on its chondroitin sulfate-glycosaminoglycans, as ChABC digestion alleviated neurite inhibition because of aggrecan. Growth cones displayed full or partial collapse on aggrecan aggregate, hyaluronan, and ChABC-treated aggrecan. Inhibition of Rho kinase (ROCK) with Y27632 increased neurite growth on some but not all of the aggrecan components tested. With NGF in the culture medium, Y27632 increased neurite outgrowth on aggrecan aggregate, monomers, and ChABC-treated aggrecan, but not on hyaluronan. The ROCK inhibitor also increased NT3-responsive outgrowth on aggrecan aggregate and hyaluronan, but not on ChABC-treated aggrecan. This study showed that the matrix proteoglycan aggrecan and its components have multiple effects on neurite outgrowth and that some of these effects involve the Rho/ROCK pathway. PMID:17918743

Chan, Carmen C M; Roberts, Clive R; Steeves, John D; Tetzlaff, Wolfram



Computer Simulation of Nerve Transfer Strategies for Restoring Shoulder Function after Adult C5-C6 Root Avulsion Injuries  

PubMed Central

Background Functional ability following nerve transfer for upper brachial plexus injuries relies on both the function and magnitude of force recovery of targeted muscles. Following nerve transfers targeting either the axillary nerve, suprascapular nerve, or both, it is unclear whether functional ability is restored in face of limited muscle force recovery. Methods We used a computer model to simulate flexing the elbow while maintaining a functional shoulder posture for 3 nerve transfer scenarios. The minimum restored force capacity necessary to perform the task, associated compensations by neighboring muscles, and the effect of altered muscle coordination on movement effort, were assessed. Results The minimum force restored by the axillary, suprascapular, and combined nerve transfers that was required for the model to simulate the desired movement was 25%, 40%, and 15% of the unimpaired muscle force capacity, respectively. When the deltoid was paralyzed, the infraspinatus and subscapularis muscles generated higher shoulder abduction moments to compensate for deltoid weakness. For all scenarios, movement effort increased as restored force capacity decreased. Conclusions Combined axillary and suprascapular nerve transfer required the least restored force capacity to perform the desired elbow flexion task, while single suprascapular nerve transfer required the most restored force capacity to perform the same task. Though compensation mechanisms allowed all scenarios to perform the desired movement despite weakened shoulder muscles, compensation increased movement effort. Dynamic simulations allowed independent evaluation of the effect of restored force capacity on functional outcome in a way that is not possible experimentally. Clinical Relevance Simultaneous nerve transfer to suprascapular and axillary nerves yields the best simulated biomechanical outcome for lower magnitudes of muscle force recovery in this computer model. Axillary nerve transfer performs nearly as well as the combined transfer, while suprascapular nerve transfer is more sensitive to the magnitude of reinnervation and therefore avoided.

Crouch, Dustin L.; Li, Zhongyu; Barnwell, Jonathan C.; Plate, Johannes F.; Daly, Melissa; Saul, Katherine R.



A temporal variation in nonneuronal protein synthesis in dorsal root ganglia and nerve and its significance to studies of axonal transport  

SciTech Connect

Protein synthesis and fast axonal transport were studied in vitro using dorsal root ganglia (DRG)-sciatic nerve preparations from the amphibian Xenopus laevis. It was observed that the rate of incorporation of (/sup 3/H)leucine into protein in DRG and isolated segments of nerve began to increase 9 to 11 h after killing the animal, attaining at 13 to 17 h a maximum of 5- to 10-times preincrease (less than 9 h) values. At the same time as an increase in the rate of incorporation began, synthesis commenced in DRG and nerve exposed to cycloheximide (125 micrograms/ml). Whereas cycloheximide reduced fast axonal transport to 1 to 3% of control values in preparations maintained 20 to 24 h in vitro, cycloheximide reduced incorporation in DRG to only 80% of control values. N-terminal labeling studies showed that both the increased incorporation and cycloheximide-insensitive incorporation resulted from protein synthesis. Autoradiographic and incorporation studies indicated that nonneuronal cells situated in the ganglion capsule and perineural sheath of the nerve were responsible for both the increased incorporation and cycloheximide-insensitive synthesis. The findings have implications for the study of axonal transport.

Snyder, R.E.; O'Brien, D.W.; Nihei, T.



Clasping of subscapular artery by radial nerve.  


The present study is about an abnormal origin of radial nerve from Posterior cord of brachial plexus .Here radial nerve was arising as two roots from the posterior cord of brachial plexus. One root was passing posterior to the subscapular artery and other root anterior and the artery was situated between the two roots of the radial nerve. Further down both the roots united to form the trunk of the radial nerve. PMID:18604032

Kuwar, R B; Bilodi, A K S


Monitoring of immune cell response to B cell depletion therapy and nerve root injury using SPIO enhanced MRI  

NASA Astrophysics Data System (ADS)

Magnetic resonance (MR) is a robust platform for non-invasive, high-resolution anatomical imaging. However, MR imaging lacks the requisite sensitivity and contrast for imaging at the cellular level. This represents a clinical impediment to greater diagnostic accuracy. Recent advances have allowed for the in vivo visualization of populations and even of individual cells using superparamagnetic iron oxide (SPIO) MR contrast agents. These nanoparticles, commonly manifested as a core of a single iron oxide crystal or cluster of crystals coated in a biocompatible shell, function to shorten proton relaxation times. In MR imaging these constructs locally dephase protons, resulting in a decrease in signal (hypointensity) localized to the region of accumulation of SPIO. In the context of immune cell imaging, SPIO can provide insight into the cellular migration patterns, trafficking, temporal dynamics and progression of diseases and their related pathological states. Furthermore, by visualizing the presence and activity of immune cells, SPIO-enabled cellular imaging can help evaluate the efficacy of therapy in immune disorders. This thesis examines the production, modification and application of SPIO in a range of in vitro and in vivo immune-response-relevant cellular systems. The role of different nanoparticle characteristics including diameter, surface charge and concentration are investigated in the labeling of T cells in culture. Following optimization of SPIO loading conditions for lymphocytes, the effect these particles have on the activation of primary B cells are elucidated. B cells are tracked using a variety of modalities, with and without the application of B cell depleting therapy. This is to evaluate the efficacy of SPIO as in vivo marker for B cell distribution. Unmodified SPIO were applied to monitor macrophage infiltration in a transient nerve root compression model, with implications for neck pain diagnosis and treatment. Nanoparticle accumulation and MR hypointensity was correlated to the presence of activated macrophage at the site of injury. Taken together, the application of SPIO to study nanoparticle uptake in vitro and visualization of immune cells in vivo provide a basis for advanced study and diagnosis of diverse pathologies.

Thorek, Daniel L.


Patients with low back pain differ from those who also have leg pain or signs of nerve root involvement - a cross-sectional study  

PubMed Central

Background Leg pain associated with low back pain (LBP) is recognized as a risk factor for a poor prognosis, and is included as a component in most LBP classification systems. The location of leg pain relative to the knee and the presence of a positive straight leg raise test have been suggested to have clinical implications. To understand differences between such leg pain subgroups, and whether differences include potentially modifiable characteristics, the purpose of this paper was to describe characteristics of patients classified into the Quebec Task Force (QTF) subgroups of: 1) LBP only, 2) LBP and pain above the knee, 3) LBP and pain below the knee, and 4) LBP and signs of nerve root involvement. Methods Analysis of routine clinical data from an outpatient department. Based on patient reported data and clinical findings, patients were allocated to the QTF subgroups and described according to the domains of pain, activity limitation, work participation, psychology, general health and clinical examination findings. Results A total of 2,673 patients aged 18–95 years (median 47) who were referred for assessment of LBP were included. Increasing severity was consistently observed across the subgroups from LBP only to LBP with signs of nerve root involvement although subgroup differences were small. LBP patients with leg pain differed from those with LBP only on a wide variety of parameters, and patients with signs of nerve root involvement had a more severe profile on almost all measures compared with other patients with back-related leg pain. Conclusion LBP patients with pain referral to the legs were more severely affected than those with local LBP, and patients with signs of nerve root involvement were the ones most severily affected. These findings underpin the concurrent validity of the Quebec Task Force Classification. However, the small size of many between-subgroup differences amid the large variability in this sample of cross-sectional data also underlines that the heterogeneity of patients with LBP is more complex than that which can be explained by leg pain patterns alone. The implications of the observed differences also require investigation in longitudinal studies.



Sacral nerve root stimulation for the treatment of urge incontinence and detrusor dysfunction utilizing a cephalocaudal intraspinal method of lead insertion: a case report.  


Sacral nerve root stimulation (SNRS) is known to be effective in the treatment of pelvic motor dysfunction(1-4). Bladder and urethral motor disorders commonly treated include urinary urge incontinence, voiding/detrusor dysfunction, and urgency/frequency syndromes. To date, neurostimulation specific to bladder and urethral dysfunction has applied a unilateral, trans-sacral approach. (Interstim, Medtronic, Minneapolis, MN) Despite some success, this method has been associated with technical failures in maintaining electrode position(5,6). As an alternative, this case report describes the selective epidural application of a cephalocaudal ("retrograde") lead insertion method in a patient with severe detrusor dysfunction and urinary urge incontinence(7). PMID:22151611

Aló, K M; Gohel, R; Corey, C L



Autotaxin and lysophosphatidic acid1 receptor-mediated demyelination of dorsal root fibers by sciatic nerve injury and intrathecal lysophosphatidylcholine  

Microsoft Academic Search

BACKGROUND: Although neuropathic pain is frequently observed in demyelinating diseases such as Guillain-Barré syndrome and multiple sclerosis, the molecular basis for the relationship between demyelination and neuropathic pain behaviors is poorly understood. Previously, we found that lysophosphatidic acid receptor (LPA1) signaling initiates sciatic nerve injury-induced neuropathic pain and demyelination. RESULTS: In the present study, we have demonstrated that sciatic nerve

Jun Nagai; Hitoshi Uchida; Yosuke Matsushita; Ryo yano; Mutsumi Ueda; Masami Niwa; Junken Aoki; Jerold Chun; Hiroshi Ueda



Virus-mediated shRNA knockdown of Na(v)1.3 in rat dorsal root ganglion attenuates nerve injury-induced neuropathic pain.  


Neuropathic pain is a chronic condition that is often refractory to treatment with available therapies and thus an unmet medical need. We have previously shown that the voltage-gated sodium channel Na(v)1.3 is upregulated in peripheral and central nervous system (CNS) of rats following nerve injury, and that it contributes to nociceptive neuron hyperexcitability in neuropathic conditions. To evaluate the therapeutic potential of peripheral Na(v)1.3 knockdown at a specific segmental level, we constructed adeno-associated viral (AAV) vector expressing small hairpin RNA against rat Na(v)1.3 and injected it into lumbar dorsal root ganglion (DRG) of rats with spared nerve injury (SNI). Our data show that direct DRG injection provides a model that can be used for proof-of-principle studies in chronic pain with respect to peripheral delivery route of gene transfer constructs, high transduction efficiency, flexibility in terms of segmental localization, and limited behavioral effects of the surgical procedure. We show that knockdown of Na(v)1.3 in lumbar 4 (L4) DRG results in an attenuation of nerve injury-induced mechanical allodynia in the SNI model. Taken together, our studies support the contribution of peripheral Na(v)1.3 to pain in adult rats with neuropathic pain, validate Na(v)1.3 as a target, and provide validation for this approach of AAV-mediated peripheral gene therapy. PMID:22910296

Samad, Omar A; Tan, Andrew M; Cheng, Xiaoyang; Foster, Edmund; Dib-Hajj, Sulayman D; Waxman, Stephen G



Differential regulation of immune responses and macrophage/neuron interactions in the dorsal root ganglion in young and adult rats following nerve injury  

PubMed Central

Background Neuropathic pain is an apparently spontaneous experience triggered by abnormal physiology of the peripheral or central nervous system, which evolves with time. Neuropathic pain arising from peripheral nerve injury is characterized by a combination of spontaneous pain, hyperalgesia and allodynia. There is no evidence of this type of pain in human infants or rat pups; brachial plexus avulsion, which causes intense neuropathic pain in adults, is not painful when the injury is sustained at birth. Since infants are capable of nociception from before birth and display both acute and chronic inflammatory pain behaviour from an early neonatal age, it appears that the mechanisms underlying neuropathic pain are differentially regulated over a prolonged postnatal period. Results We have performed a microarray analysis of the rat L4/L5 dorsal root ganglia (DRG), 7 days post spared nerve injury, a model of neuropathic pain. Genes that are regulated in adult rats displaying neuropathic behaviour were compared to those regulated in young rats (10 days old) that did not show the same neuropathic behaviour. The results show a set of genes, differentially regulated in the adult DRG, that are principally involved in immune system modulation. A functional consequence of this different immune response to injury is that resident macrophages cluster around the large A sensory neuron bodies in the adult DRG seven days post injury, whereas the macrophages in young DRG remain scattered evenly throughout the ganglion, as in controls. Conclusions The results show, for the first time, a major difference in the neuroimmune response to nerve injury in the dorsal root ganglion of young and adult rats. Differential analysis reveals a new set of immune related genes in the ganglia, that are differentially regulated in adult neuropathic pain, and that are consistent with the selective activation of macrophages around adult, but not young large A sensory neurons post injury. These differences may contribute to the reduced incidence of neuropathic pain in infants.



Spatio-temporal changes of SDF1 and its CXCR4 receptor in the dorsal root ganglia following unilateral sciatic nerve injury as a model of neuropathic pain.  


There is a growing evidence that chemokines and their receptors play a role in inducing and maintaining neuropathic pain. In the present study, unilateral chronic constriction injury (CCI) of rat sciatic nerve under aseptic conditions was used to investigate changes for stromal derived factor-1 (SDF1) and its CXCR4 receptor in lumbal (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) from both sides of naïve, CCI-operated and sham-operated rats. All CCI-operated rats displayed mechanical allodynia and thermal hyperalgesia in hind paws ipsilateral to CCI, but forepaws exhibited only temporal changes of sensitivity not correlated with alterations in SDF1 and CXCR4 proteins. Naïve DRG displayed immunofluorescence for SDF1 (SDF1-IF) in the satellite glial cells (SGC) and CXCR4-IF in the neuronal bodies with highest intensity in small- and medium-sized neurons. Immunofluorescence staining and Western blot analysis confirmed that unilateral CCI induced bilateral alterations of SDF1 and CXCR4 proteins in both L4-L5 and C7-C8 DRG. Only lumbal DRG were invaded by ED-1+ macrophages exhibiting SDF1-IF while elevation of CXCR4-IF was found in DRG neurons and SGC but not in ED-1+ macrophages. No attenuation of mechanical allodynia, but reversed thermal hyperalgesia, in ipsi- and contralateral hind paws was found in CCI-operated rats after i.p. administration of CXCR4 antagonist (AMD3100). These results indicate that SDF1/CXCR4 changes are not limited to DRG associated with injured nerve but that they also spread to DRG non-associated with such nerve. Functional involvement of these alterations in DRG non-associated with injured nerve in neuropathic pain remains to be elucidated. PMID:20127490

Dubový, Petr; Klusáková, I; Svízenská, I; Brázda, V



Neuronal expression of the ubiquitin ligase Nedd4-2 in rat dorsal root ganglia: modulation in the spared nerve injury model of neuropathic pain.  


Neuronal hyperexcitability following peripheral nerve lesions may stem from altered activity of voltage-gated sodium channels (VGSCs), which gives rise to allodynia or hyperalgesia. In vitro, the ubiquitin ligase Nedd4-2 is a negative regulator of VGSC ?-subunits (Na(v)), in particular Na(v)1.7, a key actor in nociceptor excitability. We therefore studied Nedd4-2 in rat nociceptors, its co-expression with Na(v)1.7 and Na(v)1.8, and its regulation in pathology. Adult rats were submitted to the spared nerve injury (SNI) model of neuropathic pain or injected with complete Freund's adjuvant (CFA), a model of inflammatory pain. L4 dorsal root ganglia (DRG) were analyzed in sham-operated animals, seven days after SNI and 48 h after CFA with immunofluorescence and Western blot. We observed Nedd4-2 expression in almost 50% of DRG neurons, mostly small and medium-sized. A preponderant localization is found in the non-peptidergic sub-population. Additionally, 55.7 ± 2.7% and 55.0 ± 3.6% of Nedd4-2-positive cells are co-labeled with Na(v)1.7 and Na(v)1.8 respectively. SNI significantly decreases the proportion of Nedd4-2-positive neurons from 45.9 ± 1.9% to 33.5 ± 0.7% (p<0.01) and the total Nedd4-2 protein to 44% ± 0.13% of its basal level (p<0.01, n=4 animals in each group, mean ± SEM). In contrast, no change in Nedd4-2 was found after peripheral inflammation induced by CFA. These results indicate that Nedd4-2 is present in nociceptive neurons, is downregulated after peripheral nerve injury, and might therefore contribute to the dysregulation of Na(v)s involved in the hyperexcitability associated with peripheral nerve injuries. PMID:23022218

Cachemaille, M; Laedermann, C J; Pertin, M; Abriel, H; Gosselin, R-D; Decosterd, I



Bilateral elevation of interleukin-6 protein and mRNA in both lumbar and cervical dorsal root ganglia following unilateral chronic compression injury of the sciatic nerve  

PubMed Central

Background Current research implicates interleukin (IL)-6 as a key component of the nervous-system response to injury with various effects. Methods We used unilateral chronic constriction injury (CCI) of rat sciatic nerve as a model for neuropathic pain. Immunofluorescence, ELISA, western blotting and in situ hybridization were used to investigate bilateral changes in IL-6 protein and mRNA in both lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) following CCI. The operated (CCI) and sham-operated (sham) rats were assessed after 1, 3, 7, and 14 days. Withdrawal thresholds for mechanical hyperalgesia and latencies for thermal hyperalgesia were measured in both ipsilateral and contralateral hind and fore paws. Results The ipsilateral hind paws of all CCI rats displayed a decreased threshold of mechanical hyperalgesia and withdrawal latency of thermal hyperalgesia, while the contralateral hind and fore paws of both sides exhibited no significant changes in mechanical or thermal sensitivity. No significant behavioral changes were found in the hind and fore paws on either side of the sham rats, except for thermal hypersensitivity, which was present bilaterally at 3 days. Unilateral CCI of the sciatic nerve induced a bilateral increase in IL-6 immunostaining in the neuronal bodies and satellite glial cells (SGC) surrounding neurons of both lumbar and cervical DRG, compared with those of naive control rats. This bilateral increase in IL-6 protein levels was confirmed by ELISA and western blotting. More intense staining for IL-6 mRNA was detected in lumbar and cervical DRG from both sides of rats following CCI. The DRG removed from sham rats displayed a similar pattern of staining for IL-6 protein and mRNA as found in naive DRG, but there was a higher staining intensity in SGC. Conclusions Bilateral elevation of IL-6 protein and mRNA is not limited to DRG homonymous to the injured nerve, but also extended to DRG that are heteronymous to the injured nerve. The results for IL-6 suggest that the neuroinflammatory reaction of DRG to nerve injury is propagated alongside the neuroaxis from the lumbar to the remote cervical segments. This is probably related to conditioning of cervical DRG neurons to injury.



Primary intraspinal primitive neuroectodermal tumor: case report of a tumor arising from the sacral spinal nerve root and review of the literature.  


Primary spinal primitive neuroectodermal tumor (PNET) is a rare condition, 18 cases of which have been reported in the literature. In general, this tumor is treated with surgery followed by radiotherapy and chemotherapy, but prognosis is still poor. An 18-year-old female patient with an intradural, extramedullary mass at L3-L5 levels is presented in this report. This is the first female patient with primary spinal PNET at lumbar region, second patient with spinal nerve root origin, and third one with intradural, extramedullary localization ever reported in the literature. After surgery, she was treated with craniospinal radiotherapy and four cycles of combination chemotherapy regimen consisting of vincristine, cyclophosphamide, doxorubicin alternated with ifosfamide, and VP-16. Currently, she is asymptomatic and alive at 25 months. The histopathologic, radiologic, and clinical findings of the patient are presented and relevant literature is reviewed. PMID:11943890

Yavuz, A Aydin; Yaris, Nilgun; Yavuz, Melek N; Sari, Ahmet; Reis, A Kadir; Aydin, Fazil



Contralateral femoral nerve compression: An unrecognized complication after extreme lateral interbody fusion (XLIF).  


Extreme lateral interbody fusion (XLIF) is a relatively new procedure for the treatment of degenerative disc disease avoiding the morbidity of anterior approaches. Ipsilateral L2-5 nerve root irritation and injury are well-described complications. We describe two patients with contralateral extremity symptoms, not reported so far. In the first patient the injury was caused by a displaced endplate fragment compressing the contralateral nerve root; in the second patient, the injury resulted from a far-lateral herniation after the XLIF procedure. Both patients experienced resolution of their symptoms after being reoperated. Overall, this complication was encountered in 2/32 levels treated during the study period. Overzealous endplate removal and breaking of the osteophytes in the opposite corner of the intervertebral disc, although desirable for maximal coronal deformity correction, may lead to irritation of the contralateral nerve roots. Attention is needed especially where the interbody cage is placed posteriorly or diagonally towards the neuralforamen. PMID:20965732

Papanastassiou, Ioannis D; Eleraky, Mohammad; Vrionis, Frank D



Laser-Guided Cervical Selective Nerve Root Block with the Dyna-CT: Initial Experience of Three-Dimensional Puncture Planning with an Ex-Vivo Model  

PubMed Central

Background Cervical selective nerve root block (CSNRB) is a well-established, minimally invasive procedure to treat radicular cervical pain. However, the procedure is technically challenging and might lead to major complications. The objective of this study was to evaluate the feasibility of a three-dimensional puncture planning and two-dimensional laser-guidance system for CSNRB in an ex-vivo model. Methods Dyna-CT of the cervical spine of an ex-vivo lamb model was performed with the Artis Zee® Ceiling (Siemens Medical Solutions, Erlangen, Germany) to acquire multiplanar reconstruction images. 15 cervical nerve root punctures were planned and conducted with the syngo iGuide® laser-guidance system. Needle tip location and contrast dye distribution were analyzed by two independent investigators. Procedural, planning, and fluoroscopic time, tract length, and dose area product (DAP) were acquired for each puncture. Results All 15 punctures were rated as successful with 12 punctures on the first attempt. Total procedural time was approximately 5 minutes. Mean planning time for the puncture was 2.03 (±0.39) min. Mean puncture time was 2.16 (±0.32) min, while mean fluoroscopy time was 0.17 (±0.06) min. Mean tract length was 2.68 (±0.23) cm. Mean total DAP was 397.45 (±15.63) µGy m2. Conclusion CSNRB performed with Dyna-CT and the tested laser guidance system is feasible. 3D pre-puncture planning is easy and fast and the laser-guiding system ensures very accurate and intuitive puncture control.

Al-Zghloul, Mansour; Groden, Christoph; Kerl, Hans U.




PubMed Central

Paclitaxel (Taxol®) is a frontline antineoplastic agent used to treat a variety of solid tumors including breast, ovarian, or lung cancer. The major dose limiting side effect of paclitaxel is a peripheral sensory neuropathy that can last days to a lifetime. To begin to understand the cellular events that contribute to this neuropathy, we examined a marker of cell injury/regeneration (activating transcription factor 3; ATF3), macrophage hyperplasia/hypertrophy; satellite cell hypertrophy in the dorsal root ganglion (DRG) and sciatic nerve as well as astrocyte and microglial activation within the spinal cord at 1, 4, 6 and 10 days following intravenous infusion of therapeutically relevant doses of paclitaxel. At day 1 post-infusion there was an up-regulation of ATF3 in a subpopulation of large and small DRG neurons and this up-regulation was present through day 10. In contrast, hypertrophy of DRG satellite cells, hypertrophy and hyperplasia of CD68+ macrophages in the DRG and sciatic nerve, ATF3 expression in S100?+ Schwann cells and increased expression of the microglial marker (CD11b) and the astrocyte marker glial fibrillary acidic protein in the spinal cord were not observed until day 6 post infusion. The present results demonstrate that using the time points and markers examined, DRG neurons show the first sign of injury which is followed days later by other neuropathological changes in the DRG, peripheral nerve and dorsal horn of the spinal cord. Understanding the cellular changes that generate and maintain this neuropathy may allow the development of mechanism-based therapies to attenuate or block this frequently painful and debilitating condition.

Peters, Christopher M.; Jimenez-Andrade, Juan Miguel; Kuskowski, Michael A.; Ghilardi, Joseph R.; Mantyh, Patrick W.



The neuronal architecture of the anteroventral cochlear nucleus of the cat in the region of the cochlear nerve root: Golgi and Nissl methods.  


This report characterizes the cells and fibers in one part of the cochlear nucleus, the posterior division of the anteroventral cochlear nucleus. This includes the region where the cochlear nerve root enters the brain and begins to form endings. Nissl stains reveal the somata of globular cells with dispersed Nissl substance and those of multipolar cells with coarse, clumped Nissl bodies. Both parts of the posterior division contain cells with each Nissl pattern, but in different relative numbers and locations. Golgi impregnations demonstrate two types of neurons: bushy cells, with short bush-like dendrites, and stellate and elongate cells, with long tapered dendrites. Several varieties of bushy cells, differing in the morphology of the cell body and in the size and extent of the dendritic field, can be distinguished. Comparison of the distributions of these cell types, as well as cellular morphology, suggest that the globular cells recognized in Nissl stains correspond to bushy neurons, while the multipolar cells correspond to stellate and elongate neurons. Golgi impregnations reveal large end-bulbs and smaller boutons from cochlear nerve fibers, as well as boutons from other, unidentified sources, ending in this region. The particular arrangements of the dendritic fields of the different cell types and the axonal endings associated with them indicate that these neurons must have different physiological properties, since they define different domains with respect to the cochlear and non-cochlear inputs. PMID:6186942

Tolbert, L P; Morest, D K



Vascularization of the dorsal root ganglia and peripheral nerve of the mouse: Implications for chemical-induced peripheral sensory neuropathies  

Microsoft Academic Search

Although a variety of industrial chemicals, as well as several chemotherapeutic agents used to treat cancer or HIV, preferentially induce a peripheral sensory neuropathy what remains unclear is why these agents induce a sensory vs. a motor or mixed neuropathy. Previous studies have shown that the endothelial cells that vascularize the dorsal root ganglion (DRG), which houses the primary afferent

Juan M Jimenez-Andrade; Monica B Herrera; Joseph R Ghilardi; Marina Vardanyan; Ohannes K Melemedjian; Patrick W Mantyh



Reinnervation of the rat musculocutaneous nerve stump after its direct reconnection with the C5 spinal cord segment by the nerve graft following avulsion of the ventral spinal roots: a comparison of intrathecal administration of brain-derived neurotrophic factor and Cerebrolysin  

Microsoft Academic Search

Experimental model based on the C5 ventral root avulsion was used to evaluate the efficacy of brain-derived neurotrophic factor (BDNF) and Cerebrolysin treatment on motor neuron maintenance and survival resulted in the functional reinnervation of the nerve stump. In contrast to vehicle, BDNF treatment reduced the loss and atrophy of motor neurons and enhanced the regrowth axon sprouts into the

P. Haninec; P. Dubový; F. Šámal; L. Houštava; L. Stejskal



Subtype-specific reduction of Voltage-gated Calcium Current in Medium-Sized Dorsal Root Ganglion Neurons after Painful Peripheral Nerve Injury  

PubMed Central

Sensory neurons express a variety of voltage-gated Ca2+ channel subtypes, but reports differ on their proportionate representation, and the effects of painful nerve injury on each subtype are not established. We compared levels of high-voltage activated currents in medium-sized (30-40?m) dorsal root ganglion neurons dissociated from control animals and those subjected to spinal nerve ligation, using sequential application of semiselective channel blockers (nisoldipine for L-type, SNX-111 or ?-conotoxin GVIA for N-type, agatoxin IVA or ?-Conotoxin MVIIC for P/Q-type, and SNX-482 for a component of R-type) during either square wave depolarizations or action potential waveform voltage commands. Using sequential administration of multiple blockers, proportions of total Ca2+ current attributable to different subtypes and the effect of injury depended on the sequence of blocker administration and type of depolarization command. Overall, however, N-type and L-type currents comprised the dominant components of ICa in sensory neurons under control conditions, and these subtypes showed the greatest loss of current following injury (L-type 26-71% loss, N-type 0-51% loss). Further exploration of N-type current identified by its sensitivity to ?-conotoxin GVIA applied alone showed that injury reduced the peak N-type current during step depolarization by 68% and decreased the total charge entry during action potential waveform stimulation by 44%. Isolation of N-type current by blockade of all other subtypes demonstrated a 50% loss with injury, and also revealed an injury-related rightward shift in the activation curve. Nonstationary noise analyses of N-type current in injured neurons revealed unitary channel current and number of channels that were not different from control, which indicates that injury-induced loss of current is due to a decrease in channel open probability. Our findings suggest that diminished Ca2+ influx through N-type and L-type channels may contribute to sensory neuron dysfunction and pain after nerve injury.

McCallum, J. Bruce; Wu, Hsiang-En; Tang, Qingbo; Kwok, Wai-Meng; Hogan, Quinn H.



Adrenalectomy increases the number of substance P and somatostatin immunoreactive nerve cells in the rat lumbar dorsal root ganglia.  


Using an immunocytochemical technique we have analyzed changes in substance P, somatostatin, calcitonin gene-related peptide, and galanin immunoreactivity pattern in the rat dorsal root ganglia. After 7 days of adrenalectomy, sham operated rats were compared with adrenalectomized animals either receiving a daily intraperitoneal injection of 10 mg/kg b.wt. corticosterone or vehicle. Three lumbar ganglia from each animal were blocked, serially cut, and immunostained for each neuropeptide by means of the biotin-avidin-peroxidase technique. A systematic sampling of immunoreactive ganglion cells was performed and the sample number of immunoreactive ganglion cells was calculated. After adrenalectomy, the number of substance P and somatostatin immunoreactive ganglion cells markedly increased ((means +/- S.E.M.): 245 +/- 68 versus 123 +/- 12 for sham operated animals, P < 0.01 (substance P) and 42 +/- 8 as compared to 22 +/- 9 for sham operated animals, P < 0.01 (somatostatin)). No significant changes were found in the number of calcitonin gene-related peptide and galanin immunoreactive cells after adrenalectomy. These results suggest that adrenal steroid hormones may reduce the synthesis of both substance P and somatostatin in the dorsal root ganglion cells. Daily treatment with a high dose of corticosterone, mimicking its serum levels after stress, failed to prevent the increase of peptide contents after adrenalectomy. These observations also indicate that a tonic action of corticosterone on mineralocorticoid receptors may be crucial for peptide regulation in the spinal ganglia. These results may be of relevance to adrenalectomy induced changes in sensory mechanisms, neurogenic inflammation and pain transmission and to a role of substance P and somatostatin in these processes. PMID:7516260

Coveñas, R; DeLeón, M; Chadi, G; Cintra, A; Gustafsson, J A; Narvaez, J A; Fuxe, K



Contralateral femoral nerve compression: An unrecognized complication after extreme lateral interbody fusion (XLIF)  

Microsoft Academic Search

Extreme lateral interbody fusion (XLIF) is a relatively new procedure for the treatment of degenerative disc disease avoiding the morbidity of anterior approaches. Ipsilateral L2–5 nerve root irritation and injury are well-described complications. We describe two patients with contralateral extremity symptoms, not reported so far. In the first patient the injury was caused by a displaced endplate fragment compressing the

Ioannis D. Papanastassiou; Mohammad Eleraky; Frank D. Vrionis



Caspase-2 is upregulated after sciatic nerve transection and its inhibition protects dorsal root ganglion neurons from apoptosis after serum withdrawal.  


Sciatic nerve (SN) transection-induced apoptosis of dorsal root ganglion neurons (DRGN) is one factor determining the efficacy of peripheral axonal regeneration and the return of sensation. Here, we tested the hypothesis that caspase-2 (CASP2) orchestrates apoptosis of axotomised DRGN both in vivo and in vitro by disrupting the local neurotrophic supply to DRGN. We observed significantly elevated levels of cleaved CASP2 (C-CASP2), compared to cleaved caspase-3 (C-CASP3), within TUNEL+DRGN and DRG glia (satellite and Schwann cells) after SN transection. A serum withdrawal cell culture model, which induced 40% apoptotic death in DRGN and 60% in glia, was used to model DRGN loss after neurotrophic factor withdrawal. Elevated C-CASP2 and TUNEL were observed in both DRGN and DRG glia, with C-CASP2 localisation shifting from the cytosol to the nucleus, a required step for induction of direct CASP2-mediated apoptosis. Furthermore, siRNA-mediated downregulation of CASP2 protected 50% of DRGN from apoptosis after serum withdrawal, while downregulation of CASP3 had no effect on DRGN or DRG glia survival. We conclude that CASP2 orchestrates the death of SN-axotomised DRGN directly and also indirectly through loss of DRG glia and their local neurotrophic factor support. Accordingly, inhibiting CASP2 expression is a potential therapy for improving both the SN regeneration response and peripheral sensory recovery. PMID:23451279

Vigneswara, Vasanthy; Berry, Martin; Logan, Ann; Ahmed, Zubair



p38 Mitogen-Activated Protein Kinase Is Activated after a Spinal Nerve Ligation in Spinal Cord Microglia and Dorsal Root Ganglion Neurons and Contributes to the Generation of Neuropathic Pain  

Microsoft Academic Search

The possible involvement of p38 mitogen-activated protein kinase activation in spinal cord and dorsal root ganglion (DRG) cells in the development of peripheral neuropathic pain has been explored. Ligation of the L5 spinal nerve (SNL) on one side in adult rats produces an early onset and long-lasting mechanical allodynia. This lesion results in activation of p38 in the L5 segment

Shan-Xue Jin; Zhi-Ye Zhuang; Clifford J. Woolf; Ru-Rong Ji



Nerve growth factor receptor TrkA is down-regulated during postnatal development by a subset of dorsal root ganglion neurons.  


Nerve growth factor (NGF), signaling through its receptor tyrosine kinase, TrkA, is required for the survival of all small and many intermediate-sized murine dorsal root ganglion (DRG) neurons during development, accounting for 80% of the total DRG population. Surprisingly, NGF/TrkA-dependent neurons include a large population that does not express TrkA in adult mice (Silos-Santiago et al., 1995). This finding suggests two hypotheses: Neurons lacking TrkA in the adult may express TrkA during development, or they may be maintained through a paracrine mechanism by TrkA-expressing neurons. To determine whether TrkA is expressed transiently by DRG neurons that lack the receptor in adulthood, we examined the distribution of TrkA protein during development. We show here that TrkA expression is strikingly developmentally regulated. Eighty percent of DRG neurons expressed TrkA during embryogenesis and early postnatal life, whereas only 43% expressed TrkA at postnatal day (P) 21. Because the period of TrkA down-regulation corresponds with a critical period during which nociceptive phenotype can be altered by NGF (see Lewin and Mendell [1993] Trends Neurosci. 16:353-359), we examined whether NGF modulates the down-regulation of TrkA. Surprisingly, neither NGF deprivation nor augmentation altered the extent of TrkA down-regulation. Our results demonstrate a novel form of regulation of neurotrophin receptor expression that occurs late in development. All DRG neurons that require NGF for survival express TrkA during embryogenesis, and many continue to express TrkA during a postnatal period when neuronal phenotype is regulated by NGF. The subsequent down-regulation of TrkA is likely to be importantly related to functional distinctions among nociceptive neurons in maturity. PMID:9136800

Molliver, D C; Snider, W D



Ulnar nerve tuberculoma.  


The authors report a very rare case of tuberculoma involving the ulnar nerve. The patient, a 7-year-old girl, presented with swelling over the medial aspect of her right forearm just below the elbow joint, with features of ulnar nerve palsy, including paresthesias along the little and ring fingers and claw hand deformity. There was a history of trauma and contact with a contagious case of tuberculosis. There were no other signs of tuberculosis. At surgical exploration the ulnar nerve was found to be thickened, and on opening the sheath there was evidence of caseous material enclosed in a fibrous capsule compressing and displacing the nerve fibers. The lesion, along with the capsule, was subtotally removed using curettage, and a part of the capsule that was densely adherent to the nerve fibers was left in the patient. Histopathological examination of the specimen was consistent with tuberculoma. The patient received adequate antitubercular treatment and showed significant improvement. PMID:23082843

Ramesh Chandra, V V; Prasad, Bodapati Chandramowliswara; Varaprasad, Gangumolu



Traumatic Nerve Lesions  

Microsoft Academic Search

Traumatic lesions of peripheral nerves are common. According to the literature a relevant lesion of a peripheral nerve exists\\u000a in roughly 2%–3% of patients admitted to Level I trauma centers. If plexus and root injuries are included the incidence rises\\u000a to about 5% (Noble et al. 1998; Robinson 2000). In general, these types of injuries are increasingly recognized in today’s

Siegfried Peer; Hannes Gruber


Efficacy of intraoperative monitoring of transcranial electrical stimulation-induced motor evoked potentials and spontaneous electromyography activity to identify acute-versus delayed-onset C-5 nerve root palsy during cervical spine surgery.  


Object Deltoid muscle weakness due to C-5 nerve root injury following cervical spine surgery is an uncommon but potentially debilitating complication. Symptoms can manifest upon emergence from anesthesia or days to weeks following surgery. There is conflicting evidence regarding the efficacy of spontaneous electromyography (spEMG) monitoring in detecting evolving C-5 nerve root compromise. By contrast, transcranial electrical stimulation-induced motor evoked potential (tceMEP) monitoring has been shown to be highly sensitive and specific in identifying impending C-5 injury. In this study the authors sought to 1) determine the frequency of immediate versus delayed-onset C-5 nerve root injury following cervical spine surgery, 2) identify risk factors associated with the development of C-5 palsies, and 3) determine whether tceMEP and spEMG neuromonitoring can help to identify acutely evolving C-5 injury as well as predict delayed-onset deltoid muscle paresis. Methods The authors retrospectively reviewed the neuromonitoring and surgical records of all patients who had undergone cervical spine surgery involving the C-4 and/or C-5 level in the period from 2006 to 2008. Real-time tceMEP and spEMG monitoring from the deltoid muscle was performed as part of a multimodal neuromonitoring protocol during all surgeries. Charts were reviewed to identify patients who had experienced significant changes in tceMEPs and/or episodes of neurotonic spEMG activity during surgery, as well as those who had shown new-onset deltoid weakness either immediately upon emergence from the anesthesia or in a delayed fashion. Results Two hundred twenty-nine patients undergoing 235 cervical spine surgeries involving the C4-5 level served as the study cohort. The overall incidence of perioperative C-5 nerve root injury was 5.1%. The incidence was greatest (50%) in cases with dual corpectomies at the C-4 and C-5 spinal levels. All patients who emerged from anesthesia with deltoid weakness had significant and unresolved changes in tceMEPs during surgery, whereas only 1 had remarkable spEMG activity. Sensitivity and specificity of tceMEP monitoring for identifying acute-onset deltoid weakness were 100% and 99%, respectively. By contrast, sensitivity and specificity for spEMG were only 20% and 92%, respectively. Neither modality was effective in identifying patients who demonstrated delayed-onset deltoid weakness. Conclusions The risk of new-onset deltoid muscle weakness following cervical spine surgery is greatest for patients undergoing 2-level corpectomies involving C-4 and C-5. Transcranial electrical stimulation-induced MEP monitoring is a highly sensitive and specific technique for detecting C-5 radiculopathy that manifests immediately upon waking from anesthesia. While the absence of sustained spEMG activity does not rule out nerve root irritation, the presence of excessive neurotonic discharges serves both to alert the surgeon of such potentially injurious events and to prompt neuromonitoring personnel about the need for additional tceMEP testing. Delayed-onset C-5 nerve root injury cannot be predicted by intraoperative neuromonitoring via either modality. PMID:23889183

Bhalodia, Vidya M; Schwartz, Daniel M; Sestokas, Anthony K; Bloomgarden, Gary; Arkins, Thomas; Tomak, Patrick; Gorelick, Judith; Wijesekera, Shirvinda; Beiner, John; Goodrich, Isaac



Herpes Simplex Virus Type 1 Vector-Mediated Expression of Nerve Growth Factor Protects Dorsal Root Ganglion Neurons from Peroxide Toxicity  

PubMed Central

Nerve growth factor ? subunit (?-NGF) transgene delivery and expression by herpes simplex virus type 1 (HSV-1) vectors was examined in a cell culture model of neuroprotection from hydrogen peroxide toxicity. Replication-competent (tk? K mutant background) and replication-defective (ICP4?;tk? S mutant background) vectors were engineered to contain the murine ?-NGF cDNA under transcriptional control of either the human cytomegalovirus immediate-early gene promoter (HCMV IEp) (e.g., KHN and SHN) or the latency-active promoter 2 (LAP2) (e.g., KLN and SLN) within the viral thymidine kinase (tk) locus. Infection of rat B103 and mouse N2A neuronal cell lines, 9L rat glioma cells, and Vero cells with the KHN or SHN vectors resulted in the production of ?-NGF-specific transcripts and ?-NGF protein reaching a maximum at 3 days postinfection (p.i.). NGF protein was released into the culture media in amounts ranging from 10.83 to 352.86 ng/ml, with the highest levels being achieved in B103 cells, and was capable of inducing neurite sprouting of PC-12 cells. The same vectors produced high levels of NGF in primary dorsal root ganglion (DRG) cultures at 3 days. In contrast to HCMV IEp-mediated expression, the LAP2-NGF vectors showed robust expression in primary DRG neurons at 14 days. The neuroprotective effect of vector produced NGF was assessed by its ability to inhibit hydrogen peroxide-induced neuron toxicity in primary DRG cultures. Consistent with the kinetics of vector-mediated NGF expression, HCMV-NGF vectors were effective in abrogating the toxic effects of peroxide at 3 but not 14 days p.i. whereas LAP2-NGF vector transduction inhibited apoptosis in DRG neurons at 14 days p.i. but was ineffective at 3 days p.i. Similar kinetics of NGF expression were observed with the KHN and KLN vectors in latently infected mouse trigeminal ganglia, where high levels of ?-NGF protein expression were detected at 4 wks p.i. only from the LAP2; HCMV-NGF-driven expression peaked at 3 days but could not be detected during HSV latency at 4 weeks. Together, these results indicate that (i) NGF vector-infected cells produce and secrete mature, biologically active ?-NGF; (ii) vector-synthesized NGF was capable of blocking peroxide-induced apoptosis in primary DRG cultures; and (iii) the HCMV-IEp functioned to produce high levels of NGF for several days; but (iv) only the native LAP2 was capable of long-term expression of a therapeutic gene product in latently infected neurons in vivo.

Goins, William F.; Lee, Kevin A.; Cavalcoli, James D.; O'Malley, Mark E.; DeKosky, Steven T.; Fink, David J.; Glorioso, Joseph C.



Mixed-muscle electrode placement (“jumping” muscles) may produce false-negative results when using transcranial motor evoked potentials to detect an isolated nerve root injury in a porcine model  

Microsoft Academic Search

Introduction  Placing EMG electrode pairs that span several muscles is sometimes used to enhance the efficacy of electromyographic recordings.\\u000a This technique, often referred to as “jumping,” has not been studied when using Motor Evoked Potentials (TcMEP) for detecting\\u000a isolated spinal nerve root injury during spine surgery.\\u000a \\u000a \\u000a \\u000a Methods  TcMEPs were obtained in seven pigs under general anesthesia. One pair of recording electrodes was

Russ Lyon; Shane Burch; Jeremy Lieberman



Role of motor-evoked potential monitoring in conjunction with temporary clipping of spinal nerve roots in posterior thoracic spine tumor surgery  

Microsoft Academic Search

Background contextThe vascular supply of the thoracic spinal cord depends on the thoracolumbar segmental arteries. Because of the small size and ventral course of these arteries in relation to the dorsal root ganglion and ventral root, they cannot be reliably identified during surgery by anatomic or morphologic criteria. Sacrificing them will most likely result in paraplegia.

Mohammed A. Eleraky; Matthias Setzer; Ioannis D. Papanastassiou; Ali A. Baaj; Nam D. Tran; Kiesha M. Katsares; Frank D. Vrionis



Expression of c-Fos and c-Jun in adjacent cervical spinal cord segments following C7 nerve root rhizotomy in rats: Indication of a neural pathway between adjacent cervical spinal cord segments  

PubMed Central

Cervical radiculopathy is a common disease in clinical practice. However, the symptoms are not confined to the affected spinal cord segment indicated by magnetic resonance imaging (MRI) findings. In the present study, we measured c-Fos and c-Jun expression in ipsilateral and adjacent cervical spinal cord segments following C7 nerve root rhizotomy, to determine whether there is a neural pathway between adjacent cervical spinal cord segments. Forty-eight adult male Wistar rats were randomly divided into two groups: the C7 rhizotomy group (rhizotomy group, n=24) and the sham-operated group (sham group, n=24). The right C7 nerve root was completely cut off in the rhizotomy group, while it was exposed but not cut in the sham group. The expression of c-Fos and c-Jun in cervical spinal cord segments was detected by immunohistochemistry at 2 and 4 h after surgery. We observed that the number of c-Fos- and c-Jun-positive neurons in ipsilateral C5–7 segments were significantly increased at 2 and 4 h after C7 nerve root rhizotomy (P<0.05 vs. the sham group). The location of c-Fosand c-Jun-positive neurons in C5–7 gray matter was similar in the rhizotomy and sham groups, which was mainly in lamina IX of the anterior horn and laminae I–II of the dorsal horn of the spinal cord. However, the number of c-Fos- and c-Jun-positive neurons in the C5–7 gray matter was significantly reduced at 4 h after surgery compared with the number 2 h after surgery. The location of c-Fos- and c-Jun-positive neurons at 4 h was similar with that at 2 h. Therefore, there may be a neural pathway between ipsilateral adjacent cervical spinal cord segments. This may be one possible explanation as to why the radicular symptoms of cervical radiculopathy are not confined to the affected spinal cord segment shown by MRI.




Xenografted fetal dorsal root ganglion, embryonic stem cell and adult neural stem cell survival following implantation into the adult vestibulocochlear nerve  

Microsoft Academic Search

Sensorineural hearing loss is a disabling condition. In the post-embryonic and adult mammalian inner ear, the regeneration of auditory hair cells, spiral ganglion neurons or their axons does not occur naturally. This decrease in excitable neurons limits the success of auditory rehabilitation.Allografts and xenografts have shown promise in the treatment of a variety of neurological diseases. Fetal dorsal root ganglion

C. Regala; M. Duan; J. Zou; M. Salminen; P. Olivius



Opioids and Sensory Nerves  

Microsoft Academic Search

\\u000a This chapter reviews the expression and regulation of opioid receptors in sensory neurons and the interactions of these receptors\\u000a with endogenous and exogenous opioid ligands. Inflammation of peripheral tissues leads to increased synthesis and axonal transport\\u000a of opioid receptors in dorsal root ganglion neurons. This results in opioid receptor upregulation and enhanced G protein coupling\\u000a at peripheral sensory nerve terminals.

Christoph Stein; Christian Zöllner


Nerve conduits for nerve reconstruction  

Microsoft Academic Search

Although autogenous nerve grafting remains the gold standard for repair of peripheral nerve defects, the use of various conduits can be a substitute provided these conduits meet the above-mentioned prerequisites. For the moment, autogenous vein grafts or denatured muscle grafts can be used to bridge short defects, especially in distal sensory nerves. Incorporation of muscle into a vein graft expands

Huan Wang; William C. Lineaweaver



Changes in Expression of Two Tetrodotoxin-Resistant Sodium Channels and Their Currents in Dorsal Root Ganglion Neurons after Sciatic Nerve Injury But Not Rhizotomy  

Microsoft Academic Search

Two TTX-resistant sodium channels, SNS and NaN, are prefer- entially expressed in c-type dorsal root ganglion (DRG) neurons and have been shown recently to have distinct electrophysiolog- ical signatures, SNS producing a slowly inactivating and NaN producing a persistent sodium current with a relatively hyperpo- larized voltage-dependence. An attenuation of SNS and NaN transcripts has been demonstrated in small DRG

Amanda A. Sleeper; Theodore R. Cummins; Sulayman D. Dib-Hajj; William Hormuzdiar; Lynda Tyrrell; Stephen G. Waxman; Joel A. Black



Cranial Nerves IX, X, XI, and XII  

PubMed Central

This article concludes the series on cranial nerves, with review of the final four (IX–XII). To summarize briefly, the most important and common syndrome caused by a disorder of the glossopharyngeal nerve (craniel nerve IX) is glossopharyngeal neuralgia. Also, swallowing function occasionally is compromised in a rare but disabling form of tardive dyskinesia called tardive dystonia, because the upper motor portion of the glossopharyngel nerve projects to the basal ganglia and can be affected by lesions in the basal ganglia. Vagus nerve funtion (craniel nerve X) can be compromised in schizophrenia, bulimia, obesity, and major depression. A cervical lesion to the nerve roots of the spinal accessory nerve (craniel nerve XI) can cause a cervical dystonia, which sometimes is misdiagnosed as a dyskinesia related to neuroleptic use. Finally, unilateral hypoglossal (craniel nerve XII) nerve palsy is one of the most common mononeuropathies caused by brain metastases. Supranuclear lesions of cranial nerve XII are involved in pseudobulbar palsy and ALS, and lower motor neuron lesions of cranial nerve XII can also be present in bulbar palsy and in ALS patients who also have lower motor neuron involvement. This article reviews these and other syndromes related to cranial nerves IX through XII that might be seen by psychiatry.

Sanders, Richard D.



Reinnervation of Urethral and Anal Sphincters With Femoral Motor Nerve to Pudendal Nerve Transfer  

PubMed Central

Aims Lower motor neuron damage to sacral roots or nerves can result in incontinence and a flaccid urinary bladder. We showed bladder reinnervation after transfer of coccygeal to sacral ventral roots, and genitofemoral nerves (L1, 2 origin) to pelvic nerves. This study assesses the feasibility of urethral and anal sphincter reinnervation using transfer of motor branches of the femoral nerve (L2–4 origin) to pudendal nerves (S1, 2 origin) that innervate the urethral and anal sphincters in a canine model. Methods Sacral ventral roots were selected by their ability to stimulate bladder, urethral sphincter, and anal sphincter contraction and transected. Bilaterally, branches of the femoral nerve, specifically, nervus saphenous pars muscularis [Evans HE. Miller’s anatomy of the dog. Philadelphia: W.B. Saunders; 1993], were transferred and end-to-end anastomosed to transected pudendal nerve branches in the perineum, then enclosed in unipolar nerve cuff electrodes with leads to implanted RF micro-stimulators. Results Nerve stimulation induced increased anal and urethral sphincter pressures in five of six transferred nerves. Retrograde neurotracing from the bladder, urethral sphincter, and anal sphincter using fluorogold, fast blue, and fluororuby, demonstrated urethral and anal sphincter labeled neurons in L2–4 cord segments (but not S1–3) in nerve transfer canines, consistent with rein-nervation by the transferred femoral nerve motor branches. Controls had labeled neurons only in S1–3 segments. Postmortem DiI and DiO labeling confirmed axonal regrowth across the nerve repair site. Conclusions These results show spinal cord reinnervation of urethral and anal sphincter targets after sacral ventral root transection and femoral nerve transfer (NT) to the denervated pudendal nerve. These surgical procedures may allow patients to regain continence.

Ruggieri, Michael R.; Braverman, Alan S.; Bernal, Raymond M.; Lamarre, Neil S.; Brown, Justin M.; Barbe, Mary F.



Clinical observations of the anatomy and function of the marginal mandibular nerve  

Microsoft Academic Search

The objective of this study was to assess the anatomical variation of the marginal mandibular nerve, and evaluate the risk of nerve malfunction after neck dissection. The method involved clinical assessment of the anatomy and function of the marginal mandibular nerve in 133 neck dissections. When the neck was extended the nerve was displaced in an anterior and downward direction

R. W. Nason; A. Binahmed; M. G. Torchia; J. Thliversis



Neuropathic pain after C7 spinal nerve transection in man  

Microsoft Academic Search

Various animal models of neuropathic pain have been developed which involve creating a lesion in a spinal root. We describe a human correlate in which patients developed a neuropathic pain syndrome after having one spinal nerve surgically divided. In some patients with brachial plexus lesions, the C7 spinal nerve from the opposite side is divided and used as a nerve

Zahid Ali; Richard A Meyer; Allan J Belzberg



Nerve growth factor protects adult sensory neurons from cell death and atrophy caused by nerve injury  

Microsoft Academic Search

Summary The reaction of dorsal root ganglia (DRG) neurons to axotomy and its alteration by locally supplied nerve growth factor (NGF) were examined in adult rats. Surgically implanted silicone chambers attached to the severed tip of the sciatic nerve acted as reservoirs capable of providing prolonged access of NGF to the site of injury. The time course of NGF activity

Keith M. Rich; Jack R. Luszczynski; Patricia A. Osborne; Eugene M. Johnson



Pinched Nerve  


... take about one hour: Nerve conduction study. Patch-style electrodes are placed on your skin to stimulate ... not-for-profit organization and proceeds from Web advertising help support our mission. Mayo Clinic does not ...


Nerve Injuries  


... educated." After the nerve has recovered, sensory re-education may be needed to improve feeling to the hand or finger. This involves physician therapy and the appropriate therapy based on the nature of the injury will be recommended ...


Nerve conduction  

MedlinePLUS Videos and Cool Tools

... fascicles) that contain hundreds of individual nerve fibers (neurons). Neurons consist of dendrites, axon, and cell body. The ... tree-like structures that receive signals from other neurons and from special sensory cells that sense the ...


Precision displacement reference system  


A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

Bieg, Lothar F. (Albuquerque, NM); Dubois, Robert R. (Albuquerque, NM); Strother, Jerry D. (Edgewood, NM)



Tactile suppression of displacement.  


In vision, the discovery of the phenomenon of saccadic suppression of displacement has made important contributions to the understanding of the stable world problem. Here, we report a similar phenomenon in the tactile modality. When scanning a single Braille dot with two fingers of the same hand, participants were asked to decide whether the dot was stationary or whether it was displaced from one location to another. The stimulus was produced by refreshable Braille devices that have dots that can be swiftly raised and recessed. In some conditions, the dot was stationary. In others, a displacement was created by monitoring the participant's finger position and by switching the dot activation when it was not touched by either finger. The dot displacement was of either 2.5 mm or 5 mm. We found that in certain cases, displaced dots were felt to be stationary. If the displacement was orthogonal to the finger movements, tactile suppression occurred effectively when it was of 2.5 mm, but when the displacement was of 5 mm, the participants easily detected it. If the displacement was medial-lateral, the suppression effect occurred as well, but less often when the apparent movement of the dot opposed the movement of the finger. In such cases, the stimulus appeared sooner than when the brain could predict it from finger movement, supporting a predictive rather than a postdictive differential processing hypothesis. PMID:20842353

Ziat, Mounia; Hayward, Vincent; Chapman, C Elaine; Ernst, Marc O; Lenay, Charles



The displaced aggression questionnaire.  


Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to engage in displaced aggression). The trait measure demonstrated good internal consistency and test-retest reliability as well as convergent and discriminant construct validity. Unlike other related personality measures, trait displaced aggression significantly predicted indirect indicators of real-world displaced aggression (i.e., self-reported domestic abuse and road rage) as well as laboratory displaced aggression in 2 experiments. PMID:16784350

Denson, Thomas F; Pedersen, William C; Miller, Norman



Inferior alveolar nerve injuries associated with mandibular fractures.  


The study evaluates the incidence of inferior alveolar nerve injuries in mandibular fractures, the duration of their recovery, and the factors associated with them. Fifty-two patients with mandibular fractures involving the ramus, angle, and body regions were included in this study; the inferior alveolar nerve was examined for neurological deficit posttraumatically using sharp/blunt differentiation method, and during the follow-up period the progression of neural recovery was assessed. The incidence of neural injury of the inferior alveolar nerve was 42.3%, comminuted and displaced linear fractures were associated with higher incidence of inferior alveolar nerve injury and prolonged recovery time, and recovery of inferior alveolar nerve function occurred in 91%.Fractures of the mandible involving the ramus, angle, and body regions, and comminuted and displaced linear fractures are factors that increase the incidence of inferior alveolar nerve injuries. Missile injuries can be considered as another risk factor. PMID:23147318

Bede, Salwan Yousif Hanna; Ismael, Waleed Khaleel; Al-Assaf, Dhuha A; Omer, Saad Salem



Internal Displacement Monitoring Centre  

NSDL National Science Digital Library

The Internal Displacement Monitoring Centre (IDMC) was established twelve years ago in the hope that they would "raise awareness of the plight of internally displaced people (IDP), point to gaps in national and international responses and promote solutions reflecting international standards and best practices." The Centre also keeps a database of 50 countries in which people have been displaced within their own country due to conflicts or human rights violations. To get a sense of where displaced persons are and how many countries have IDPs, visitors can click on the small world map on the far right hand side of the homepage. Scrolling over the map will reveal the number of displaced people by continent. Visitors interested in learning about an individual country can click on the continent, then click on one of the countries for an "Internal Displacement Profile", "Country Statistics", and an "Overview". The Resources tab, at the top of any page, includes "IDMC Publications", "Picture Galleries" of internally displaced people in India, Cyprus, and the West Bank, to name a few, and "IDP Maps" which has dozens of maps of from 2001 to 2009.


Nerve Racking  

NSDL National Science Digital Library

This lesson describes the function and components of the human nervous system. It helps students understand the purpose of our brain, spinal cord, nerves and the five senses. How the nervous system is affected during spaceflight is also discussed in this lesson.

Integrated Teaching And Learning Program


Kinematics Problem: Displacement  

NSDL National Science Digital Library

A bowling ball is lifted from rest onto a shelf by an external agent (position is in meters and time is in seconds). Rank the paths by the displacement of the bowling ball during the animations (greatest first).

Christian, Wolfgang; Belloni, Mario



Precision Displacement Mechanism (PDM).  

National Technical Information Service (NTIS)

A mechanism designed to fulfill the requirements of the Precision Displacement Mechanism (PDM) for the Far Infrared and Submillimeter Space Telescope (FIRST) antenna is described. The PDM function is to perform the fine adjustment of the position of the m...

J. I. Bueno F. Delcampo P. Coste



Peripheral nerve regeneration through optic nerve grafts  

Microsoft Academic Search

Grafts of optic nerve were placed end-toend with the proximal stumps of severed common peroneal nerves in inbred mice. It was found that fraying the proximal end of adult optic nerve grafts to disrupt the glia limitans increased their chances of being penetrated by regenerating peripheral nerve fibres. Suturing grafts to the proximal stump also enhanced their penetration by axons.

P. N. Anderson; P. Woodham; M. Turmaine



Root systems  

NSDL National Science Digital Library

One purpose that roots serve is that of anchoring the plant in the ground. Roots also take up water and nutrients for the plant. Plants all have different root system types to fit their individual needs and locations.

N/A N/A (U.S. Government;)



Activation of phosphatidylinositol 3-kinase and protein kinase B\\/Akt in dorsal root ganglia and spinal cord contributes to the neuropathic pain induced by spinal nerve ligation in rats  

Microsoft Academic Search

Several lines of evidence indicate that phosphatidylinositol 3-kinase (PI3K) and PI3K-protein kinase B\\/Akt (PKB\\/Akt) signal pathway mediate the pain hypersensitivity induced by intradermal injection of capsaicin or nerve growth factor. However, the role of PI3K and PI3K-PKB\\/Akt signal pathway activation in neuropathic pain is still unclear. Using L5 spinal nerve ligation (L5 SNL) and immunohistochemistry, we found that the numbers

Ji-Tian Xu; Hui-Yin Tu; Wen-Jun Xin; Xian-Guo Liu; Gui-Hong Zhang; Cai-Hong Zhai



Considerations in nerve repair  

Microsoft Academic Search

ome nerve injuries require repair in order to regain sen- sory or motor function. Although this article focuses pri- marily on trigeminal nerve (TN) injuries and repairs, the facts presented may apply to any peripheral nerve repair. The primary indications for nerve repair or grafting are 1) an injury or continuity defect in a nerve, as a result of trauma,



Signal strength versus cuff length in nerve cuff electrode recordings  

Microsoft Academic Search

When a nerve cuff electrode is used for the recording of signals from peripheral nerves, cuff dimensions have to be chosen. Traditionally, the peak-to-peak amplitude of the single-fiber action potential (SFAP) is optimized through the choice of cuff diameter and cuff length. In this paper, the dependency of the root-mean-square (RMS) value of the nerve signal on the cuff dimensions

Lotte N. S. Andreasen; Johannes J. Struijk



Gravisensitivity of cress roots  

NASA Astrophysics Data System (ADS)

The minimum dose (stimulus x time [gs]) eliciting a visible gravitropic response, has been determined using continuous and intermittent stimulation and two different accelerations at 1g and 0.1g. The minimum dose of 20 - 30 gs estimated for microgravity roots and of 50 - 60 gs for roots grown on a 1g-centrifuge indicated a higher sensitivity of microgravity roots. Applying intermittent stimuli to microgravity-grown roots, gravitropic responses were observed after two stimuli of 13.5 gs separated by a stimulus free interval of 118 s. The curvature of microgravity-grown roots to lateral stimulation by 0.1 g was remarkably smaller than by 1g in spite of the same doses which were applied to the seedlings. Microscopic investigations corresponding to stimulations in the range of the threshold values, demonstrated small displacement (< 2 ?m) of statoliths in root statocytes. Accepting the statolith theory, one can conclude that stimulus transformation has to occur in the cytoplasm in close vicinity to the statoliths and that this transformation system was affected during seedling cultivation in microgravity.

Volkmann, Dieter; Tewinkel, Martin


No sympathetic nerve sprouting in rat trigeminal ganglion following painful and non-painful infraorbital nerve neuropathy  

Microsoft Academic Search

Following sciatic nerve injury sympathetic invasion and basket formation is seen in dorsal root ganglia. We examined whether this phenomenon occurs in trigeminal ganglion (TG) following axotomy (IOAx) or chronic constriction injury to the infraorbital nerve (IOCCI). The IOCCI rats developed hyperresponsiveness to pinprick stimulation consistent with this model and the IOAx rats remained hyporesponsive for most of the study

Rafael Benoliel; Eli Eliav; Michael Tal



Global displacement models 1  

Microsoft Academic Search

An introduction into global displacement models is presented. The local dynamical equation in the Eulerian and the Lagrangean description is reviewed with reference to stress tensors of type Cauchy, Piola, Kirchhoff and Finger. Constitutive equations for linear viscoelastic material with isotropic prestress are discussed. The role of frame velocity and frame acceleration or of Coriolis acceleration, Euler acceleration (gyroscopic or

E. W. Grafarend



Character displacement in Hydrobia  

Microsoft Academic Search

Fenchel's study of size variation in Hydrobiid snails in the Limfjord, Denmark, provides one of the most convincing cases of ecological character displacement available. In order to assess the generality of the phenomena within the Hydrobia genus, allopatric and sympatric Hydrobia ventrosa, H. neglecta and H. ulvae were collected from 24 coastal sites around Eastern England in July and October,

A. J. Cherrill; R. James



Romanticism displaced and placeless  

Microsoft Academic Search

Displacement, deriving mainly from the circumstances of the first modern world war, is an abiding notion in European Romanticism. It can take the form of a fragmentation of psychic identity through loss of nationality, as we find in Ugo Foscolo, or of the exile’s split between nationalist identities, as exemplified by Germaine de Staël’s Corinne. But in the literature of

Stuart Curran



Tidal station displacements  

Microsoft Academic Search

Theoretical modeling of the station displacements produced by tidal deformations of the Earth due to lunisolar gravitational forces is a necessary part of the analysis of space geodetic data. To attain the accuracies demanded by the precision of the data, a generalized version of the Love number formalism has to be used wherein the classical Love and Shida numbers are

P. M. Mathews; V. Dehant; John M. Gipson



Nerve conduction velocity  


Nerve conduction velocity (NCV) is a test to see how fast electrical signals move through a nerve. ... travel between electrodes are used to determine the speed of the nerve signals. Electromyography (recording from needles ...


Nerve Impulses in Plants  

ERIC Educational Resources Information Center

|Summarizes research done on the resting and action potential of nerve impulses, electrical excitation of nerve cells, electrical properties of Nitella, and temperature effects on action potential. (GS)|

Blatt, F. J.



Nerve Impulses in Plants  

ERIC Educational Resources Information Center

Summarizes research done on the resting and action potential of nerve impulses, electrical excitation of nerve cells, electrical properties of Nitella, and temperature effects on action potential. (GS)

Blatt, F. J.



Displaced patella fractures.  


Displaced patella fractures often result in disruption of the extensor mechanism of the knee. An intact extensor mechanism is a requirement for unassisted gait. Therefore, operative treatment of the displaced patella fracture is generally recommended. The evaluation of the patella fracture patient includes examination of extensor mechanism integrity. Operative management of patella fractures normally includes open reduction with internal fixation, although partial patellectomy is occasionally performed, with advancement of quadriceps tendon or patellar ligament to the fracture bed. Open reduction with internal fixation has historically been performed utilizing anterior tension band wiring, although comminution of the fracture occasionally makes this fixation construct inadequate. Supplementation or replacement of the tension band wire construct with interfragmentary screws, cerclage wire or suture, and/or plate-and-screw constructs may add to the stability of the fixation construct. Arthrosis of the patellofemoral joint is very common after healing of patella fractures, and substantial functional deficits may persist long after fracture healing has occurred. PMID:23966286

Della Rocca, Gregory J



The Displaced Aggression Questionnaire  

Microsoft Academic Search

Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to

Thomas F. Denson; William C. Pedersen; Norman Miller



Above Water: Buoyancy & Displacement  

NSDL National Science Digital Library

In an investigation called "Shape It!" learners craft tiny boats out of clay, set them afloat on water and then add weight loads to them, in order to explore: how objects stay afloat in water; what the relationship is among surface tension, buoyancy, density and displacement; and how shape, size, and type of material affect an object's ability to remain buoyant. The introductory text discusses how heavy steel ships can float on bodies of water like rivers, bays and oceans.

Jersey, New; Center, Liberty S.; Coalition, New J.



RTV 21 Displacements  

SciTech Connect

A seal is needed for the cover of the Nitrogen Test Vessel in order to prevent leakage of the N{sub 2} gas. This seal is to be molded out of RTV 21. In this experiment, the Modulus of Elasticity of the RTV was sought after, and the displacements of the RTV due to various stresses were measured to see if they were large enough to provide a tight seal between the vessel and its cover.

Kurita, C.H.; /Fermilab




Microsoft Academic Search

We experienced two cases of inferior alveolar nerve paresthesia caused by root canal medicaments, which were successfully relieved by microscopic endodontic treatment. In the first case, the paresthesia might have been attributable to infiltration of calcium hydroxide into the mandibular canal through the root canals of the mandibular left second molar tooth. In the second case, the paresthesia might have




Effects of lumbar sympathectomy on pain behavioral changes caused by nucleus pulposus-induced spinal nerve damage in rats  

Microsoft Academic Search

It has been suggested that lumbar sympathectomy can reduce pain behavior, including mechanical allodynia and thermal hyperalgesia, caused by ligation of the spinal nerve. One well-characterized model, which involves application of nucleus pulposus to the spinal nerve and displacement of the adjacent nerve, shows behavioral changes in rats. However, there have been no previous reports regarding sympathectomy performed in this

Yasuaki Murata; Kjell Olmarker; Ichiro Takahashi; Kazuhisa Takahashi; Björn Rydevik



Digital Fiber Optic Displacement Sensors.  

National Technical Information Service (NTIS)

A digital fiber optic displacement sensor using a Mach-Zehnder interferometer was tested. The theoretical sensitivity of digital interferometer displacement sensors, and the dual polarization method are presented. Experimental results show that interferom...

N. Fuerstenau



[X-ray computed tomography of lumbosacral roots and primary hypertrophic neuritis (Dejerine-Sottas disease)].  


CT without contrast of lumbosacral nerve roots was performed in 13 patients with peroneal atrophy and 28 control subjects. Two series of 5 mm serial sections parallel to the plane of the disk were examined at the L4-L5 and L5-S1 levels, and the transverse diameter of the S1 nerve roots measured at the lower part of the lateral recess. Results showed frank bilateral, grossly symmetrical hypertrophy of lumbosacral roots in 8 of the 13 patients. This hypertrophy involved all roots examined (L4, L5, S1), except in one case where only S1 roots were involved. Hypertrophy was often more marked on the distal part of the roots and on spinal nerves, contrasting with the sometimes normal or only slightly altered appearance of the nerve roots emerging from the dural sac. In these 8 cases, the diameter of the S1 nerve roots was 8 to 18 mm, in contrast to a mean of 3.5 +/- 1 mm in the 28 controls. CT scan images were normal in the remaining 5 patients. The presence of a CT image of nerve hypertrophy was in all cases associated with a marked fall in nerve conduction rate (median nerve motor conduction rate less than 25 msec-1), and a decrease in number of myelinated fibers with numerous onion bulbs. In contrast, the absence of CT nerve hypertrophy could not predict the results of electrophysiological and histological examinations. PMID:2749098

Mas, J L; Buthiau, D; Fallet-Bianco, C; Cheron, F; Raulo, P; de Recondo, J; Rondot, P



The nerve branches to the external anal sphincter: the macroscopic supply and microscopic structure  

Microsoft Academic Search

Summary  The study was performed using 45 pelvic half section specimens (41 fetal ones and four adults). The macroscopic dissection\\u000a followed the nerve branches from their spinal roots up to the external anal sphincter. Three nerve branches were found: the\\u000a anterior ramus arising from the external perineal nerve, the inferior rectal nerve and an independent posterior branch. The\\u000a anterior and the

C Gagnard; G Godlewski; D Prat; O Lan; J Cousineau; Y Maklouf




Microsoft Academic Search

Displacement-based seismic design and assessment of structures require the reliable definition of displacement spectra for a wide range of periods and damping levels. The displacement spectra derived from acceleration spectra in existing seismic codes do not provide a suitable answer and there are no existing frequency-dependent attenuation relationships derived specifically for this purpose. Using a carefully processed dataset of European





Microsoft Academic Search

Direct pump control of hydraulic systems is more energy efficient than throttle valve based methods to control hydra ulic systems. This requires variable displacement pumps that are responsive and capable of electronic control. Such Electronic Displacement Controlled (EDC) pumps tend to be significantl y larger, heavier and more expensive than fixed displacement c oun- terparts. In addition, achievable control bandwidths

Perry Y. Li; Cassie Y. Li; Thomas R. Chase


Histochemical study of the postnatal development of autonomic nerves in the mouse iris, using a whole-mount preparation method.  


Postnatal development of autonomic nerves in the mouse iris was studied histochemically from one day to five months of age. For the demonstration of aminergic nerves the glyoxylic acid method was used, while for cholinergic nerves, Karnovsky and Roots' method was utilized on the whole-mount preparations of irises. The results obtained were as follows. In one-day-old mice, many aminergic nerves could already be seen, while cholinergic nerves were scarcely observable. Both types of nerve increased rapidly in the first 2 weeks. Both completed development between 3 and 4 weeks, although aminergic nerves were observed to develop earlier than the cholinergic. PMID:7107324

Tsukahara, S; Kobayashi, S; Sugita, K; Nagata, T



Variable displacement blower  


A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

Bookout, Charles C. (Niskayuna, NY); Stotts, Robert E. (Clifton Park, NY); Waring, Douglass R. (Ballston Spa, NY); Folsom, Lawrence R. (Ohain, BE)



Ulnar nerve damage (image)  


... arm. The nerve is commonly injured at the elbow because of elbow fracture or dislocation. The ulnar nerve is near ... surface of the body where it crosses the elbow, so prolonged pressure on the elbow or entrapment ...


Nerves and Tissue Repair.  

National Technical Information Service (NTIS)

Studies have been conducted with regenerating amphibian sciatic nerves in organ culture to characterize further transport and release of transferrin in growing axons of peripheral nerves. The hypothesis under investigation is that transferrin, the iron-tr...

A. L. Mescher



Tibial nerve dysfunction  


... nerve dysfunction is a loss of movement or sensation in the foot from damage to the tibial ... the leg. The tibial nerve supplies movement and sensation to the calf and foot muscles. A problem ...


Optic Nerve Disorders  


... each eye carries impulses to the brain, where visual information is interpreted. Damage to an optic nerve ... determine where the problem is in the pathway. Visual Pathways and the Consequences of Damage Nerve signals ...


Common peroneal nerve dysfunction  


... type of peripheral neuropathy (damage to nerves outside the brain or spinal cord). This condition can affect people ... people: Who are very thin (for example, from anorexia nervosa ) ... damage the common peroneal nerve Charcot-Marie-Tooth disease is ...


Nerve Injuries in Athletes.  

ERIC Educational Resources Information Center

|Over a two-year period this study evaluated the condition of 65 athletes with nerve injuries. These injuries represent the spectrum of nerve injuries likely to be encountered in sports medicine clinics. (Author/MT)|

Collins, Kathryn; And Others



Skin and Nerve Biopsies  

Center for Drug Evaluation (CDER)

Text VersionPage 1. Skin and Nerve Biopsies RA Malik Page 2. ... Nerve Biopsy • Evidence from Clinical Trials • Skin Biopsy • Evidence from Clinical Trials ... More results from


Protein–water displacement distributions  

Microsoft Academic Search

The statistical properties of fast protein–water motions are analyzed by dynamic neutron scattering experiments. Using isotopic exchange, one probes either protein or water hydrogen displacements. A moment analysis of the scattering function in the time domain yields model-independent information such as time-resolved mean square displacements and the Gauss-deviation. From the moments, one can reconstruct the displacement distribution. Hydration water displays

Wolfgang Doster; Marcus Settles



An unusual complication of ulnar nerve entrapment in a pediatric olecranon fracture: a case report.  


The rates of rare complications of acute or late ulnar nerve entrapment after supracondylar fractures, medial condyl fractures, elbow dislocations, forearm fractures, Galeazzi fracture dislocations, and epiphyseal separation of the distal ulna were reported earlier in the literature. Here, we report a late ulnar nerve entrapment after displaced olecranon fracture in a 10-year-old boy. PMID:19369899

Ertem, Kadir



Engineering peripheral nerve repair.  


Current approaches for treating peripheral nerve injury have resulted in promising, yet insufficient functional recovery compared to the clinical standard of care, autologous nerve grafts. In order to design a construct that can match the regenerative potential of the autograft, all facets of nerve tissue must be incorporated in a combinatorial therapy. Engineered biomaterial scaffolds in the future will have to promote enhanced regeneration and appropriate reinnervation by targeting the highly sensitive response of regenerating nerves to their surrounding microenvironment. PMID:23790730

Marquardt, Laura M; Sakiyama-Elbert, Shelly E



MRI of displaced meniscal fragments.  


A torn meniscus frequently requires surgical fixation or debridement as definitive treatment. Meniscal tears with associated fragment displacement, such as bucket handle and flap tears, can be difficult to recognize and accurately describe on MRI, and displaced fragments can be challenging to identify at surgery. A displaced meniscal fragment can be obscured by synovium or be in a location not usually evaluated at arthroscopy. We present a pictorial essay of meniscal tears with displaced fragments in patients referred to a pediatric hospital in order to increase recognition and accurate interpretation by the radiologist, who in turn can help assist the surgeon in planning appropriate therapy. PMID:21863288

Dunoski, Brian; Zbojniewicz, Andrew M; Laor, Tal



Sciatic nerve: sonographic evaluation and anatomic-pathologic considerations.  


Sonographic analysis of the sciatic nerve was performed in vitro (anatomic specimen), in vivo (healthy volunteers), and in 16 patients with suspected peripheral sciatic nerve lesions. The ultrasound (US) examinations were performed with standard and high-resolution US equipment with linear-array configuration. The normal nerve displayed an echogenic fibrillar texture with round cross-sectional structure on both in vitro and in vivo sonograms. Satisfactory delineation of the nerve was obtainable in all cases. Nerve displacement was the main sonographic finding in cases of extrinsic compression. The lesion displayed variable echotexture, ranging from hypoechogenicity or mixed echogenicity in hematomata to hyperechogenicity in cases of fibrosis. Primary nerve tumors (neurofibroma) or infiltrating tumors (desmoid) caused clear disruption of the nerve structure. Use of sonography enabled assessment of the continuity of the nerve margins with the interposed graft in a case of reconstructive surgery. The potential to image sciatic nerve lesions noninvasively may have an important impact on diagnosis, treatment, and prognosis in symptomatic patients. PMID:1924780

Graif, M; Seton, A; Nerubai, J; Horoszowski, H; Itzchak, Y



Cranial Nerves Model  

NSDL National Science Digital Library

Lesson is designed to introduce students to cranial nerves through the use of an introductory lecture. Students will then create a three-dimensional model of the cranial nerves. An information sheet will accompany the model in order to help students learn crucial aspects of the cranial nerves.

Juliann Garza (University of Texas-Pan American Physician Assistant Studies)



Characteristics of Nerve Agents.  

National Technical Information Service (NTIS)

There are three types of nerve agents currently stored in chemical stockpiles in the United States: VX, GB and GA. All three nerve agents are members of the organophosphate family. Nerve agent VX, a clear, odorless and tasteless liquid, has an appearance ...




Microsoft Academic Search

Biologists have long known that closely related species are often phenotypically different where they occur together, but are indistinguishable where they occur alone. The causes of such character displacement are controversial, however. We used polyphenic spadefoot toad tadpoles (Spea bombifrons and S. multiplicata) to test the hypothesis that character displacement evolves to minimize competition for food. We also sought to

David W. Pfennig; Peter J. Murphy



Displacement cascades in diatomic materials  

SciTech Connect

A new function, the specified-projectile displacement function p/sub ijk/ (E), is introduced to describe displacement cascades in polyatomic materials. This function describes the specific collision events that produce displacements and hence adds new information not previously available. Calculations of p/sub ijk/ (E) for MgO, Al/sub 2/O/sub 3/ and TaO are presented and discussed. Results show that the parameters that have the largest effect on displacement collision events are the PKA energy and the mass ratio of the atom types in the material. It is further shown that the microscopic nature of the displacement events changes over the entire recoil energy range relevant to fusion neutron spectra and that these changes are different in materials whose mass ratio is near one than in those where it is far from one.

Parkin, D.M.; Coulter, C.A.



Optic Nerve Elongation  

PubMed Central

The length of the optic nerves is a reflection of normal postnatal cranio-orbital development. Unilateral elongation of an optic nerve has been observed in two patients with orbital and skull base neoplasms. In the first case as compared to the patient's opposite, normal optic nerve, an elongated length of the involved optic nerve of 45 mm was present. The involved optic nerve in the second patient was 10 mm longer than the normal opposite optic nerve. The visual and extraocular function was preserved in the second patient. The first patient had only light perception in the affected eye. In this paper, the embryology, anatomy, and physiology of the optic nerve and its mechanisms of stretch and repair are discussed. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8Figure 9Figure 10Figure 11Figure 13

Alvi, Aijaz; Janecka, Ivo P.; Kapadia, Silloo; Johnson, Bruce L.; McVay, William



Chromatolysis of dorsal root ganglion cells studied by cryofixation  

Microsoft Academic Search

Cytoskeletal alterations in the cytoplasm of chromatolytic neurons of the dorsal root ganglia were studied in chickens after transection of the sciatic nerves. These studies were carried out using cryofixation with a nitrogencooled propane jet. By this method, the morphological complexity of the cytoskeleton in normal perikarya and cell processes can be visualized. The cytoskeleton of the dorsal root ganglion

Karl Meller



Behavioral and pharmacological characterization of a distal peripheral nerve injury in the rat.  


Previous rat neuropathic pain models have utilized peripheral nerve injuries that damage a significant proportion of large nerves such as the sciatic nerve or its divisions. Injuries that lead to neuropathic pain in humans may involve the peripheral extremities. The current study evaluated the behavioral effects of injury to the plantar nerves in the rat (distal nerve injury-DNI). A delayed onset of hypersensitivity to an innocuous mechanical stimulus was observed following cutting of the left plantar nerves, whereas mechanical hypersensitivity developed more rapidly in rats with either an injury near the sciatic nerve trunk (chronic constriction injury (CCI), spared nerve injury (SNI)) or a spinal nerve root (spinal nerve ligation (SNL). Similar to other nerve injury pain models, rats with injured plantar nerves also developed an early onset and persistent sensitivity to a cooling stimulus. The effects of morphine, gabapentin and imipramine on mechanical and cold hypersensitivity were evaluated in rats with a DNI, CCI and SNI. In all three models, morphine dose-dependently suppressed mechanical and cold hypersensitivity, whereas gabapentin only suppressed mechanical hypersensitivity. Imipramine had no effect on either cold or mechanical hypersensitivity in any of the nerve-injured rats. The pharmacological data suggest that the underlying basis of neuropathic pain may be similar irrespective of the site of nerve injury. PMID:15894076

Hama, Aldric T; Borsook, David



Histochemical study of the postnatal development of autonomic nerves in the mouse iris, using a whole-mount preparation method  

Microsoft Academic Search

Postnatal development of autonomic nerves in the mouse iris was studied histochemically from one day to five months of age. For the demonstration of aminergic nerves the glyoxylic acid method was used, while for cholinergic nerves, Karnovsky and Roots' method was utilized on the whole-mount preparations of irises. The results obtained were as follows. In one-day-old mice, many aminergic nerves

S. Tsukahara; S. Kobayashi; K. Sugita; T. Nagata



Gastric mucosal nerve density  

PubMed Central

Background: Autonomic neuropathy is a frequent diagnosis for the gastrointestinal symptoms or postural hypotension experienced by patients with longstanding diabetes. However, neuropathologic evidence to substantiate the diagnosis is limited. We hypothesized that quantification of nerves in gastric mucosa would confirm the presence of autonomic neuropathy. Methods: Mucosal biopsies from the stomach antrum and fundus were obtained during endoscopy from 15 healthy controls and 13 type 1 diabetic candidates for pancreas transplantation who had secondary diabetic complications affecting the eyes, kidneys, and nerves, including a diagnosis of gastroparesis. Neurologic status was evaluated by neurologic examination, nerve conduction studies, and skin biopsy. Biopsies were processed to quantify gastric mucosal nerves and epidermal nerves. Results: Gastric mucosal nerves from diabetic subjects had reduced density and abnormal morphology compared to control subjects (p < 0.05). The horizontal and vertical meshwork pattern of nerve fibers that normally extends from the base of gastric glands to the basal lamina underlying the epithelial surface was deficient in diabetic subjects. Eleven of the 13 diabetic patients had residual food in the stomach after overnight fasting. Neurologic abnormalities on clinical examination were found in 12 of 13 diabetic subjects and nerve conduction studies were abnormal in all patients. The epidermal nerve fiber density was deficient in skin biopsies from diabetic subjects. Conclusions: In this observational study, gastric mucosal nerves were abnormal in patients with type 1 diabetes with secondary complications and clinical evidence of gastroparesis. Gastric mucosal biopsy is a safe, practical method for histologic diagnosis of gastric autonomic neuropathy.

Selim, M.M.; Wendelschafer-Crabb, G.; Redmon, J.B.; Khoruts, A.; Hodges, J.S.; Koch, K.; Walk, D.; Kennedy, W.R.



Peripheral nerve regeneration and neurotrophic factors  

PubMed Central

The role of neurotrophic factors in the maintenance and survival of peripheral neuronal cells has been the subject of numerous studies. Administration of exogenous neurotrophic factors after nerve injury has been shown to mimic the effect of target organ-derived trophic factors on neuronal cells. After axotomy and during peripheral nerve regeneration, the neurotrophins NGF, NT-3 and BDNF show a well defined and selective beneficial effect on the survival and phenotypic expression of primary sensory neurons in dorsal root ganglia and of motoneurons in spinal cord. Other neurotrophic factors such as CNTF, GDNF and LIF also exert a variety of actions on neuronal cells, which appear to overlap and complement those of the neurotrophins. In addition, there is an indirect contribution of GGF to nerve regeneration. GGF is produced by neurons and stimulates proliferation of Schwann cells, underlining the close interaction between neuronal and glial cells during peripheral nerve regeneration. Different possibilities have been investigated for the delivery of growth factors to the injured neurons, in search of a suitable system for clinical applications. The studies reviewed in this article show the therapeutic potential of neurotrophic factors for the treatment of peripheral nerve injury and for neuropathies.




Optical stimulation of peripheral nerves in vivo  

NASA Astrophysics Data System (ADS)

This dissertation documents the emergence and validation of a new clinical tool that bridges the fields of biomedical optics and neuroscience. The research herein describes an innovative method for direct neurostimulation with pulsed infrared laser light. Safety and effectiveness of this technique are first demonstrated through functional stimulation of the rat sciatic nerve in vivo. The Holmium:YAG laser (lambda = 2.12 mum) is shown to operate at an optimal wavelength for peripheral nerve stimulation with advantages over standard electrical neural stimulation; including contact-free stimulation, high spatial selectivity, and lack of a stimulation artifact. The underlying biophysical mechanism responsible for transient optical nerve stimulation appears to be a small, absorption driven thermal gradient sustained at the axonal layer of nerve. Results explicitly prove that low frequency optical stimulation can reliably stimulate without resulting in tissue thermal damage. Based on the positive results from animal studies, these optimal laser parameters were utilized to move this research into the clinic with a combined safety and efficacy study in human subjects undergoing selective dorsal rhizotomy. The clinical Holmium:YAG laser was used to effectively stimulate human dorsal spinal roots and elicit functional muscle responses recorded during surgery without evidence of nerve damage. Overall these results predict that this technology can be a valuable clinical tool in various neurosurgical applications.

Wells, Jonathon D.


Borehole optical lateral displacement sensor  


There is provided by this invention an optical displacement sensor that utilizes a reflective target connected to a surface to be monitored to reflect light from a light source such that the reflected light is received by a photoelectric transducer. The electric signal from the photoelectric transducer is then imputed into electronic circuitry to generate an electronic image of the target. The target`s image is monitored to determine the quantity and direction of any lateral displacement in the target`s image which represents lateral displacement in the surface being monitored. 4 figs.

Lewis, R.E.



[Peripheral nerve disorders--clinical pathological approaches].  


Clinical pathological approach is defined as combination of neurological, neurophysiological and neuroradiological findings for the interpretation of the morphology of the sural nerve. For this purpose, first, the usefulness of simultaneous biopsy of sural nerve and ipsilateral short peroneal muscle was presented. This method has helped establish the diagnosis of angitis or amyloidosis in some cases. Furthermore, motor-dominant clinical picture was ascertained by relative preservation of sural nerve in contrast with severe changes in intramuscular nerve fascicles. Second, histochemistry using UEA-1 lectin to detect somatic sensory C fibers was discussed. UEA-1 specifically binds to unmyelinated axons and small neurons in dorsal root ganglia as well as substantia gelatinosa of the spinal cord. Serial semithin and ultrathin sections were obtained. The semithin section was removed of epon and stained histochemically with UEA-1. Positive fibers in the semithin section was compared with the counterpart in the ultrathin sections. UEA-1 positive fibers were found to comprise 20% of all unmyelinated fibers and be randomly distributed among the entire nerve fascicles. The application of this technique to pathological specimens is now undergoing. Third, an autopsy case with sarin intoxication was reported as an example of systemic study of the peripheral nervous system. The patient was a 51-year-old man who inhaled sarin in the attack of Tokyo Subway. He fell into vegetative state and was passively maintained for 13 months. Peripheral sensory nerve showed typical pattern of dying back-type distal peripheral axonopathy. It might be indicated that peripheral nerve be carefully checked among the sarin victims. In conclusion, the aim of our approach is to combine all clinical information, introduce recent advance in neuroscience, and try to find possible cure to intractable neurological disorders. PMID:9577657

Murayama, S



Using CIDS with Displaced Workers.  

ERIC Educational Resources Information Center

|Discusses the use of the Virginia Vital Information for Education and Work program at J. Sargeant Reynolds Community College, with particular emphasis on career planning and placement services and outreach efforts. Highlights special displaced workers programs with industry. (DMM)|

Amburgey, Lillian; Sanborn, Carleton H.



Nerve and Blood Vessels  

Microsoft Academic Search

From the histologic point of view, nerves are round or flattened cords, with a complex internal structure made of myelinated\\u000a and unmyelinated nerve fibers, containing axons and Schwann cells grouped in fascicles (Fig. 4.1a) (Erickson 1997). Along the course of the nerve, fibers can traverse from one fascicle to another and fascicles can split and merge. Based\\u000a on the fascicular

Maura Valle; Maria Pia Zamorani


Histochemical studies on the postnatal development of autonomic nerves in mice cerebral arteries  

Microsoft Academic Search

Postnatal development of autonomic nerves of major cerebral arteries was histochemically studied in mice from one day to five months of age. For demonstration of aminergic nerves the glyoxylic acid method was used, while for cholinergic nerves Karnovsky and Roots' technique was utilized consecutively on the same whole mount preparations. The results obtained were as follows:1)In one-day-old mice a few

S. Kobayashi; S. Tsukahara; K. Sugita; K. Matsuo; T. Nagata



Cool-sensitive Neurons in the Ventral Nerve Cord of Crustaceans  

Microsoft Academic Search

The firing properties and distribution of the cool-sensitive neurons in the ventral nerve cord were studied in four crustacean species (Panulirus japonicus, Penaeus japonicus, Homarus americanus and Ligia exotica). Several efferent axons in each of the three nerve roots (r1, r2, r3) initiated impulses or raised frequency of spontaneous impulses when the isolated nerve cord was cooled for 3–5 min.

Masaki Tani; Taketeru Kuramoto



Nerve monitoring changes related to iliac artery compression during anterior lumbar spine surgery  

Microsoft Academic Search

BACKGROUND CONTEXT: There are no studies in the literature that correlate compression of the iliac vessels resulting in obstruction of blood flow with changes in nerve monitoring parameters during anterior lumbar surgery.PURPOSE: To determine whether there is significant compression of the iliac vessels that can cause temporary nerve root ischemia or limb ischemia that could be responsible for loss of

Salvador A Brau; Mark J Spoonamore; Lance Snyder; Constance Gilbert; Georgia Rhonda; Lytton A Williams; Robert G Watkins



Stimulation of the greater occipital nerve induces increased central excitability of dural afferent input  

Microsoft Academic Search

Summary Patients with primary headaches often report pain that involves not only the front of the head, innervated by the first (ophthalmic) division of the trigeminal nerve, but also the back of the head, innervated by the greater occipital nerve (GON) that is a branch of the C2 spinal root. The aim of this work was to study the physiology

Thorsten Bartsch; Peter J. Goadsby



Neuromuscular disease: Rehabilitation and electrodiagnosis. 1. Anatomy and physiology of nerve and muscle  

Microsoft Academic Search

This article of the Self-Directed Physiatric Education Program to assist practitioners and trainees in physical medicine and rehabilitation identifies the anatomy and physiology of nerve, neuromuscular junction, and muscle as they relate to rehabilitation of diseases affecting these structures. Structural relationships of the spinal roots, peripheral nerves, motor units, and muscle fibers are outlined, with structural, functional, and electrodiagnostic correlations.

Virginia Graziani



Development of purinergic sensitivity in sensory neurons after peripheral nerve injury in the rat  

Microsoft Academic Search

Purinoceptors are present in the cell bodies as well as in both peripheral and central terminals of many sensory neurons, where they may play a role in sensory transmission, including pain. After peripheral nerve injury at the spinal nerve level, some axotomized afferent neurons develop ongoing discharges (ectopic discharges) that originate in the dorsal root ganglion (DRG). In the present

Junli Zhou; Kyungsoon Chung; Jin Mo Chung



Plasticity in the expression of bradykinin binding sites in sensory neurons after mechanical nerve injury  

Microsoft Academic Search

The pro-inflammatory mediator bradykinin plays an important role in hyperalgesia during inflammatory conditions. Here, we used unilateral ligation of the sciatic nerve to investigate whether the expression of bradykinin binding sites in isolated rat dorsal root ganglion neurons is changed following nerve injury. Under control conditions, the percentage of neurons expressing bradykinin binding sites increased from 52% at day 0.8

M Petersen; A. S Eckert; G Segond von Banchet; B Heppelmann; A Klusch; K.-D Kniffki



Clavicle fracture with intrathoracic displacement.  


Clavicle fractures are common, and most are isolated injuries. Injury to the nearby subclavian vessels and brachial plexus have classically been described as potential complications of clavicle fractures. However, in the setting of a substantially displaced clavicle fracture, concomitant thoracic trauma is relatively frequent. Injury to the thorax can be difficult to identify on physical examination, and advanced imaging modalities may be required for diagnosis. The evaluation, workup, and management of a patient with intrathoracic displacement of a clavicle fracture are described. Despite the significant fracture displacement and associated pneumothorax, the injury severity was not clinically obvious. Imaging, including a screening chest radiograph and subsequent axial computed tomography, played an important role in diagnosis and management. The patient underwent successful open reduction and plate fixation. A thoracostomy tube was not required at any point during the hospitalization. The patient recovered uneventfully and returned to full work duty by 3 months postoperatively. Including the current report, only 3 cases of intrathoracic displacement of the clavicle have been published in the English literature. All involved fractures of the middle third of the clavicle. The severity of displacement was not obvious in any patient, and diagnosis was dependent on additional imaging. Given the frequency of associated chest trauma and limitations of physical examination, chest radiography should be considered in the evaluation of patients with substantially displaced clavicle fractures. PMID:23937761

Lohse, Grant R; Lee, Donald H



Lingual nerve injury after use of a cuffed oropharyngeal airway.  


The cuffed oropharyngeal airway is a modified Guedel airway and is recommended for anaesthesia in spontaneously breathing patients. To our knowledge this is the first report of transient unilateral lingual nerve palsy after the use of a cuffed oropharyngeal airway to maintain anaesthesia during arthroscopy of an ankle. The aetiology of lingual nerve damage is multifactorial. The possible mechanisms involved include anterior displacement of the mandible during insertion of the cuffed oropharyngeal airway (as in the jaw thrust manoeuvre), compression of the nerve against the mandible, or stretching of the nerve over the hyoglossus by the cuff of the cuffed oropharyngeal airway. We recommend gentle airway manipulation with the use of the cuffed oropharyngeal airway, avoidance of excessive cuff inflation and early recognition of such a complication if it occurs. PMID:11350466

Kadry, M A; Popat, M T



[Facial nerve paralysis and mandibular fracture].  


The authors describe three cases of peripheral facial nerve paralysis in patients with a mandibular fracture. In two cases, in which the onset of palsy was uncertain, the facial nerve injury was contralateral to the fractured side. Topodiagnostic tests showed neural damage at the third intrapetrosal portion and at the genicular ganglion. In one of the two patients tomography revealed a fracture line through the anterio-superior wall of the external auditory canal homolateral to the facial palsy. In the third subject palsy set in immediately after the trauma and was ipsilateral to the mandibular fracture; the facial lesion was localized at the genicular ganglion. In the first two cases, functional recovery was spontaneous (40 and 0 days after the trauma respectively). In the third subject, the nerve was decompressed surgically with a complete functional recovery two months later. The functional and clinical findings of these three cases show that a contralateral facial palsy secondary to a mandibular fracture resolves spontaneously while the traumatic displacement of the mandibular condyle may determine a temporal bone fracture sometimes followed by a lesion in the intratemporal portion of the facial nerve. An event such as the latter may delay functional recovery and thus warrant surgery such as in cases of Bell's palsy. PMID:1298156

Salonna, I; Fanizzi, P; Quaranta, A


Monkey Median Nerve Repaired by Nerve Graft or Collagen Nerve Guide Tube  

Microsoft Academic Search

Nerve regeneration was followed in 15 median and 1 ulnar nerve of eight Macaca fascicularis monkeys by serial elec- trophysiological assessments over a period of three and a half years. Nerve gaps of 5 mm at the wrist were bridged by collagen-based nerve guides, nerve autografts, or direct suture repairs. Thenar muscle reinnervation occurred be- tween 50 and 70 d

S. J. Archibald; J. Shefner; C. Krarup; R. D. Madison



Reflex regulation of airway sympathetic nerves in guinea-pigs  

PubMed Central

Sympathetic nerves innervate the airways of most species but their reflex regulation has been essentially unstudied. Here we demonstrate sympathetic nerve-mediated reflex relaxation of airway smooth muscle measured in situ in the guinea-pig trachea. Retrograde tracing, immunohistochemistry and electrophysiological analysis identified a population of substance P-containing capsaicin-sensitive spinal afferent neurones in the upper thoracic (T1–T4) dorsal root ganglia (DRG) that innervate the airways and lung. After bilateral vagotomy, atropine pretreatment and precontraction of the trachealis with histamine, nebulized capsaicin (10–60 ?m) evoked a 63 ± 7% reversal of the histamine-induced contraction of the trachealis. Either the ?-adrenoceptor antagonist propranolol (2 ?m, administered directly to the trachea) or bilateral sympathetic nerve denervation of the trachea essentially abolished these reflexes (10 ± 9% and 6 ± 4% relaxations, respectively), suggesting that they were mediated primarily, if not exclusively, by sympathetic adrenergic nerve activation. Cutting the upper thoracic dorsal roots carrying the central processes of airway spinal afferents also markedly blocked the relaxations (9 ± 5% relaxation). Comparable inhibitory effects were observed following intravenous pretreatment with neurokinin receptor antagonists (3 ± 7% relaxations). These reflexes were not accompanied by consistent changes in heart rate or blood pressure. By contrast, stimulating the rostral cut ends of the cervical vagus nerves also evoked a sympathetic adrenergic nerve-mediated relaxation that were accompanied by marked alterations in blood pressure. The results indicate that the capsaicin-induced reflex-mediated relaxation of airway smooth muscle following vagotomy is mediated by sequential activation of tachykinin-containing spinal afferent and sympathetic efferent nerves innervating airways. This sympathetic nerve-mediated response may serve to oppose airway contraction induced by parasympathetic nerve activation in the airways.

Oh, Eun Joo; Mazzone, Stuart B; Canning, Brendan J; Weinreich, Daniel



Avian enteric nerve plexuses  

Microsoft Academic Search

The enteric nerve plexuses of the domestic fowl (Gallus domesticus) were investigated in sections and stretch preparations by means of the cholinesterase and glyoxylic acid fluorescence histochemical techniques. Cholinesterase-positive and varicose and non-varicose fluorescent nerve fibres were distributed at all levels of the gut in myenteric, submucosal, muscle and mucosal plexuses, and in a perivascular plexus. The density of the

H. A. Ali; J. McLelland



Nerves of Simplicial Complexes.  

National Technical Information Service (NTIS)

If a simplicial complex K is considered as covered by its maximal (closed) faces, its nerve N(K) may be defined in the usual manner. Generalizing known results on interchange graphs of graphs, simplicial complexes which are nerves of d-dimensional simplic...

B. Grunbaum



Peripheral nerve and muscle.  


This review of the past year's literature on neurophysiology of muscles and peripheral nerves emphasizes areas with direct clinical interest. The subject is diversified but will be discussed under the following major headings: nerve conduction studies, electromyography, magnetic motor evoked potentials, quantitative sensory testing, assessment of peripheral pain fibers, and autonomic function assessment. PMID:8293143

Jamal, G A; Mann, C



[Obturator nerve block].  


Obturator nerve block is commonly used for transurethral resections of the bladder in order to inhibit reflectory adductor muscle reaction during electrocoagulation and to reduce the risk of bladder wall perforation during transurethral surgery. Furthermore, obturator block is used to complete regional blocks for major knee surgery in addition to femoral and sciatic nerve blocks. Continuous techniques are sometimes used to treat chronic pain problems such as adductor spasm. During a so called "3 in 1" block (femoral nerve block) the obturator nerve will only be anaesthetized in 0-62% of the patients. Therefore, a specific approach to the obturator nerve is deemed appropriate. In addition, an accessory branch of the obturator nerve will accompany the femoral nerve in 10-30% of the patients. The classical approach uses the tuberculum pubicum as an anatomical landmark, inserting the needle approximately 1.5cm lateral and caudal until bone contact is established. After laterocaudal redirection the canalis obturatorius is reached and the local anaesthetic is injected. The alternative approach is more often used: At the proximal tendon insertion of the adductor longus muscle the needle is introduced and advanced towards the anterior superior iliac spine. For both approaches a nerve stimulator is used and 15-20ml of local anaesthetic solution are injected. PMID:20455186

Freisburger, Christian; Nachtigall, Bernd; Wulf, Hinnerk



Brain derived nerve growth factor induces spinal noradrenergic fiber sprouting and enhances clonidine analgesia following nerve injury in rats  

PubMed Central

Many treatments for neuropathic pain activate or augment norepinephrine release in the spinal cord, yet these treatments are less effective against acute nociceptive stimuli. We previously showed in mice that peripheral nerve injury results in sprouting of spinal noradrenergic fibers, possibly reflecting the substrate for this shift in drug efficacy. Here we tested whether such sprouting also occurs in rats after nerve injury and examined one signal for such sprouting. Ligation of L5 and L6 spinal nerves unilaterally in rats resulted in hypersensitivity to tactile stimulation of the ipsilateral paw, and sprouting of noradrenergic fibers in the dorsal horn of the lumbar spinal cord. Brain derived nerve growth factor (BDNF) content increased in L4–L6 dorsal root ganglia ipsilateral to injury and in lumbar spinal cord following nerve injury, and intrathecal infusion of BDNF antiserum prevented spinal noradrenergic sprouting. This treatment also prevented the increased analgesic efficacy of intrathecal clonidine observed after nerve injury. Intraspinal injection of BDNF in non-injured rats mimicked the sprouting of spinal noradrenergic fibers seen after nerve injury. These results suggest that increased BDNF synthesis and release drives spinal noradrenergic sprouting following nerve injury, and that this sprouting may paradoxically increase the capacity for analgesia in the setting of neuropathic pain from drugs which utilize or mimic the noradrenergic pathway.

Hayashida, Ken-ichiro; Clayton, Bridgette A.; Johnson, James E.; Eisenach, James C.



The nerve injury and the dying neurons: diagnosis and prevention.  


Following distal nerve injury significant sensory neuronal cell death occurs in the dorsal root ganglia, while after a more proximal injury, such as brachial plexus injury, a sizeable proportion of spinal motoneurons also undergo cell death. This phenomenon has been undervalued for a long time, but it has a significant role in the lack of functional recuperation, as neuronal cells cannot divide and be replaced, hence the resulting nerve regeneration is usually suboptimal. It is now accepted that this cell death is due to apoptosis, as indicated by analysis of specific genes involved in the apoptotic signalling cascade. Immediate nerve repair, either by direct suturing or nerve grafting, gives a degree of neuroprotection, but this approach does not fully prevent neuronal cell death and importantly it is not always possible. Our work has shown that pharmacological intervention using either acetyl-L-carnitine (ALCAR) or N-acetyl-cysteine (NAC) give complete neuroprotection in different types of peripheral nerve injury. Both compounds are clinically safe and experimental work has defined the best dose, timing after injury and duration of administration. The efficacy of neuroprotection of ALCAR and NAC can be monitored non-invasively using MRI, as demonstrated experimentally and more recently by clinical studies of the volume of dorsal root ganglia. Translation to patients of this pharmacological intervention requires further work, but the available results indicate that this approach will help to secure a better functional outcome following peripheral nerve injury and repair. PMID:22058229

Terenghi, Giorgio; Hart, Andrew; Wiberg, Mikael



Multiple displacement motor driven power drive unit  

Microsoft Academic Search

A multiple displacement motor driven power drive unit having two separate hydraulic systems each with a variable displacement hydraulic motor having its output connected to a torque summing gear train. A control provides for operation of one or the other of the motors at full displacement while the other motor is at zero displacement and free-wheels. There is a manual




A Nerve Cuff Electrode for Controlled Reshaping of Nerve Geometry  

Microsoft Academic Search

The purpose of this study is the development of a nerve electrode that reorganizes nerve geometry slowly and controllably. The Flat Interface Nerve Electrode (FINE) can reshape the nerve into an elongated oval and provide selective stimulation. However, the rate of closure of this electrode is difficult to control. The Slowly Closing - FINE (SC-FINE) is designed with an opening

Anthony V. Caparso; Dominique M. Durand; Joseph M. Mansour



Whole sensory nerve recordings with spiral nerve cuff electrode  

Microsoft Academic Search

We have used a self-curling nerve cuff electrode to record sensory information from a cutaneous nerve. This type of cuffs has previously been used only for stimulation, but its mechanical properties could make it very suitable for recording also, since it can be fitted closer to the nerve than traditional cuffs without compromising the nerve. In this study we show

T. Sinjar; B. Hinge; A. Jorgensen; M. L. Jensen; M. Haugland



Percutaneous peripheral nerve stimulation.  


Since its inception in the 1970s, peripheral neuromodulation has become an increasingly common procedure to treat chronic neuropathic disorders. Historically, peripheral nerve stimulation (PNS) originated with the placement of large surface cuff electrodes, which was refined by the introduction of functional nerve mapping with circumferential electrical stimulation. This substantially improved the targeting of sensory fascicles. Surgical placement of spinal cord stimulation (SCS) 'button type' paddle electrodes was replaced when the introduction of percutaneous cylindrical SCS electrodes expanded the spectrum of PNS applications and improved the ability to target afferent sensory fibers as well as reducing the complication rate. To further refine functional mapping for the placement of these percutaneous electrodes, radiofrequency needle probes have more recently been employed to elicit paresthesias in awake patients to map the pain generators and guide treatment. In this chapter, we provide a description of the development and basic mechanisms of peripheral nerve stimulation, as well as a more detailed description of the two most commonly employed forms of peripheral nerve stimulation: occipital nerve stimulation for occipital neuralgia, and subcutaneous peripheral nerve field stimulation to stimulate free nerve endings within the subcutaneous tissue when the pain is limited to a small, well-localized area. The closely related ideas of internal and external targeted subcutaneous stimulation are also discussed. PMID:21422775

Aló, Kenneth M; Abramova, Marina V; Richter, Erich O



Perineural tumor spread - Interconnection between spinal and cranial nerves.  


The secondary neoplastic involvement of the cervical plexus in patients with head and neck malignancies is extremely rare. MR examination of the neck revealed the diffuse neoplastic infiltration of the right C2 root, in a 57-year-old patient with several months long pain in the right ear region and a history of the tongue squamous cell carcinoma. Associated perineural tumor spread and consequent distal involvement of great auricular nerve and vagus nerve were evident. Best of our knowledge, this is the first reported involvement of the cervical plexus in patients with head and neck cancers, associated with the clearly documented interconnection between the cervical plexus and cranial nerves via great auricular nerve. PMID:23010545

Kozi?, Duško; Njagulj, Vesna; Ga?eša, Jelena Popadi?; Semnic, Robert; Prvulovi?, Nataša



Reinnervation of hind limb extremity after lumbar dorsal root ganglion injury.  


Loss of dorsal root ganglion neuron, or injury to dorsal roots, induces permanent somatosensory defect without therapeutic option. We explored an approach to restoring hind limb somatosensory innervation after elimination of L4, L5 and L6 dorsal root ganglion neurons in rats. Somatosensory pathways were reconstructed by connecting L4, L5 and L6 lumbar dorsal roots to T10, T11 and T12 intercostal nerves, respectively, thus allowing elongation of thoracic ganglion neuron peripheral axons into the sciatic nerve. Connection of thoracic dorsal root ganglion neurons to peripheral tissues was documented 4 and 7 months after injury. Myelinated and unmyelinated fibers regrew in the sciatic nerve. Nerve terminations expressing calcitonin-gene-related-peptide colonized the footpad skin. Retrograde tracing showed that T10, T11 and T12 dorsal root ganglion neurons expressing calcitonin-gene-related-peptide or the neurofilament RT97 projected axons to the sciatic nerve and the footpad skin. Recording of somatosensory evoked potentials in the upper spinal cord indicated connection between the sciatic nerve and the central nervous system. Hind limb retraction in response to nociceptive stimulation of the reinnervated footpads and reversion of skin lesions suggested partial recovery of sensory function. Proprioceptive defects persisted. Delayed somatosensory reinnervation of the hind limb after destruction of lumbar dorsal root neurons in rats indicates potential approaches to reduce chronic disability after severe injury to somatosensory pathways. PMID:16202409

Liu, Song; Bréjot, Thomas; Cressant, Arnaud; Bacci, Josette; Saïd, Gérard; Tadié, Marc; Heard, Jean Michel



Glossopharyngeal Nerve Schwannoma  

PubMed Central

Complete resection with conservation of cranial nerves is the primary goal of contemporary surgery for lower cranial nerve tumors. We describe the case of a patient with a schwannoma of the left glossopharyngeal nerve, operated on in our Neurosurgical Unit. The far lateral approach combined with laminectomy of the posterior arch of C1 was done in two steps. The procedure allowed total tumor resection and was found to be better than classic unilateral suboccipital or combined supra- and infratentorial approaches. The advantages and disadvantages of the far lateral transcondylar approach, compared to the other more common approaches, are discussed. ImagesFigure 1Figure 2

Puzzilli, F.; Mastronardi, L.; Agrillo, U.; Nardi, P.



Suprascapular nerve entrapment.  


It is important to be aware of neuropathy involving the suprascapular nerve. While direct trauma to the suprascapular nerve is the usual cause (direct blow to the base of the neck or posterior shoulder, shoulder dislocation or fracture), the problem may result from overuse injuries (such as repetitive tennis serving or spiking of a volley ball), excessive horizontal adduction, weight lifting, backpacking or no apparent reason. These last three years we have operated 8 cases of suprascapular nerve neurolysis at the level of suprascapular incision, and section of the transverse scapular ligament through the back supraspinal approach. PMID:15830964

Corò, L; Azuelos, A; Alexandre, A



[Nerve injuries in children].  


Management of peripheral nerve lesions in children does not differ fundamentally from that in adults. Nevertheless, difficulty to perform an extensive clinical examination can explain initial misdiagnosis and postoperative follow up can be tricky. The poor compliance of the children in the postoperative care makes a postoperative immobilization mandatory. If the peripheral nerve injuries involving children have a better prognosis reputation than in adults, fundamental studies results do not comfort this conventional wisdom, but rather claim for a better adaptability of the child to the relapses left by the peripheral nerves lesions. PMID:23751426

Legré, R; Iniesta, A; Toméi, F; Gay, A



Sectoral Change and Worker Displacement.  

National Technical Information Service (NTIS)

The research addresses dislocated worker problems and provides a comprehensive view of worker displacement and its role in the evolution of unemployment patterns over the past twenty-five years. The first part of the study measures a aggregate rate of wor...

R. Topel K. Murphy S. Davis L. Katz



Stochastic Microgeometry for Displacement Mapping  

Microsoft Academic Search

Creating surfaces with intricate small-scale features (mi- crogeometry) and detail is an important task in geomet- ric modeling and computer graphics. We present a model processing method capable of producing a wide variety of complex surface features based on displacement mapping and stochastic geometry. The latter is a branch of mathe- matics that analyzes and characterizes the statistical prop- erties

Craig A. Schroeder; David E. Breen; Christopher D. Cera; William C. Regli



Job Displacement, Disability, and Divorce  

Microsoft Academic Search

Earnings shocks should affect divorce probability by changing a couple's expected gains from marriage. We find that the divorce hazard rises after a spouse's job displacement but does not change after a spousal disability. This difference casts doubt on a purely pecuniary motivation for divorce following earnings shocks, since both types of shocks exhibit similar long-run economic consequences. Furthermore, the



Knowledge Integration and Displaced Volume  

Microsoft Academic Search

This study contrasted spontaneous and reflective knowledge integration instruction delivered using a computer learning environment to enhance understanding of displaced volume. Both forms of instruction provided animated experiments and required students to predict outcomes, observe results, and explain their ideas. In addition, the reflective instruction diagnosed specific inconsistencies in student reasoning and encouraged students to reflect on these dilemmas as

Marcia C. Linn; Bat-Sheva Eylon



Mass Media Displacement and Saturation  

Microsoft Academic Search

This study addresses the contradiction between the theoretical displacement of incumbent media by new media versus empirical evidence of rising consumption of both new and incumbent media. By analyzing 4 years of biannual daypart media consumption surveys, this research reveals trends in the consumer use of advertiser-supported media in the United States. Large gains were seen in new media, such

Jay Newell; Joseph J. Pilotta; John C. Thomas



Guest displacement in silicon clathrates  

Microsoft Academic Search

We study both theoretically and experimentally the structure of the doped silicon clathrate II NaxSi34. We find that contrary to published works, the sodium atoms do not retain the Td symmetry inside the Si28 cages and move about 1 Å away from the center of the cage. This displacement, in conjunction with that of a sodium atom in an adjacent

Florent Tournus; Bruno Masenelli; Patrice Mélinon; Damien Connétable; Xavier Blase; Anne Marie Flank; Pierre Lagarde; Christian Cros; Michel Pouchard




EPA Science Inventory

A new recreation site or improvement of an existing site results in an increase in demand for that site perhaps at the expense of substitute facilities. A brief literature review indicates differing views on how benefits from displaced facilities should be treated. The author dem...


Retraining Displaced Workers. Policy Brief  

ERIC Educational Resources Information Center

|Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

LaLonde, Robert; Sullivan, Daniel



Retraining Displaced Workers. Policy Brief  

ERIC Educational Resources Information Center

Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

LaLonde, Robert; Sullivan, Daniel



Whole nerve recordings with the spiral nerve cuff electrode  

Microsoft Academic Search

The feasibility of whole nerve recordings from the hypoglossal (HG) nerve is demonstrated in acute cats using the spiral nerve cuff electrode. A good contact between the nerve and the electrodes, provided by the spiral nerve cuff due to its self-coiling property, should improve the signal-to-noise ratio. An instrumentation amplifier with very low input noise characteristics is also utilized. The

Mesut Sahin; Dominique M. Durand; Musa A. Haxhiu



Complications of peripheral nerve blocks.  


Complications of peripheral nerve blocks are fortunately rare, but can be devastating for both the patient and the anaesthesiologist. This review will concentrate on current knowledge about peripheral nerve injury secondary to nerve blocks, complications from continuous peripheral nerve catheter techniques, and local anaesthetic systemic toxicity. PMID:21148659

Jeng, C L; Torrillo, T M; Rosenblatt, M A



Interfacial effects in oil displacements  

SciTech Connect

The surface stress-deformation behavior of some real phase interfaces, such as crude oil-brine interfaces, is believed to be viscoelastic. In an effort to provide a general framework for understanding such behavior, the author has proposed the simple surface material, for which the present stress is determined by the past history of only the surface deformation gradient. After considering the concept of isotropy, the author is led to isotropic simple surface materials and the simple surface fluid. The linear Boussinesq surface fluid is a limiting case of the simple surface fluid, for which the relaxation time of the surface is so short or the flow so slow that memory effects disappear. Both the measurement of surface viscoelastic behavior and its effect upon the entrapment and displacement of residual oil are discussed. Unstable foams are used for mobility control in the displacement of residual oil by carbon dioxide or nitrogen. A qualitative analysis is developed for the displacement of an unstable foam in a porous media. The effects of the magnitude of the London-van der Waals forces, of the surface tension, of the surface viscosities, of the quality (volume fraction of the gas), of the bubble size, and of the viscosity of the foaming agent solution are investigated. Finally, a statistical structural model is used in the context of local volume averaging to examine the effects of interfacial tension, the interfacial viscosities, and wetting upon the capillary pressure and relative permeability functions in an unsteady-state displacement. Within the immediate the neighborhood of a displacement front, simulations, especially of inhibitions, should employ unsteady-state relative permeabilities.

Ramamohan, T.R.



Bladder emptying by intermittent electrical stimulation of the pudendal nerve  

NASA Astrophysics Data System (ADS)

Persons with a suprasacral spinal cord injury cannot empty their bladder voluntarily. Bladder emptying can be restored by intermittent electrical stimulation of the sacral nerve roots (SR) to cause bladder contraction. However, this therapy requires sensory nerve transection to prevent dyssynergic contraction of the external urethral sphincter (EUS). Stimulation of the compound pudendal nerve trunk (PN) activates spinal micturition circuitry, leading to a reflex bladder contraction without a reflex EUS contraction. The present study determined if PN stimulation could produce bladder emptying without nerve transection in cats anesthetized with ?-chloralose. With all nerves intact, intermittent PN stimulation emptied the bladder (64 ± 14% of initial volume, n = 37 across six cats) more effectively than either distention-evoked micturition (40 ± 19%, p < 0.001, n = 27 across six cats) or bilateral intermittent SR stimulation (25 ± 23%, p < 0.005, n = 4 across two cats). After bilateral transection of the nerves innervating the urethral sphincter, intermittent SR stimulation voided 79 ± 17% (n = 12 across three cats), comparable to clinical results obtained with SR stimulation. Voiding via intermittent PN stimulation did not increase after neurotomy (p > 0.10), indicating that PN stimulation was not limited by bladder-sphincter dyssynergia. Intermittent PN stimulation holds promise for restoring bladder emptying following spinal injury without requiring nerve transection.

Boggs, Joseph W.; Wenzel, Brian J.; Gustafson, Kenneth J.; Grill, Warren M.



Ulnar nerve dysfunction  


... surface of the body where it crosses the elbow. The damage destroys the nerve covering ( myelin sheath) ... be caused by: Long-term pressure on the elbow An elbow fracture or dislocation Temporary pain and ...


Understanding facial nerve paralysis.  


Facial nerve paralysis has many causes and can be acute or chronic. Understanding the signs and symptoms, performing a careful patient evaluation, and obtaining appropriate diagnostic testing can help guide clinicians and improve outcomes. PMID:24153089

Matthaeus, Jaime; Hayden, Richard; Kim, Michael; Donald, Carrlene



Cervical Radiculopathy (Pinched Nerve)  


... Copyright 2010 American Academy of Orthopaedic Surgeons Cervical Radiculopathy (Pinched Nerve) Some people have neck pain that ... The medical term for this condition is cervical radiculopathy. Understanding your spine and how it works can ...


Diabetic Nerve Problems  


... the wrong times. This damage is called diabetic neuropathy. Over half of people with diabetes get it. ... change positions quickly Your doctor will diagnose diabetic neuropathy with a physical exam and nerve tests. Controlling ...


Role of the hypoglossal nerve in equine nasopharyngeal stability.  


The equine upper airway is highly adapted to provide the extremely high oxygen demand associated with strenuous aerobic exercise in this species. The tongue musculature, innervated by the hypoglossal nerve, plays an important role in airway stability in humans who also have a highly adapted upper airway to allow speech. The role of the hypoglossal nerve in stabilizing the equine upper airway has not been established. Isolated tongues from eight mature horses were dissected to determine the distal anatomy and branching of the equine hypoglossal nerve. Using this information, a peripheral nerve location technique was used to perform bilateral block of the common trunk of the hypoglossal nerve in 10 horses. Each horse was subjected to two trials with bilateral hypoglossal nerve block and two control trials (unblocked). Upper airway stability at exercise was determined using videoendoscopy and measurement of tracheal and pharyngeal pressure. Three main nerve branches were identified, medial and lateral branches and a discrete branch that innervated the geniohyoid muscle alone. Bilateral hypoglossal block induced nasopharyngeal instability in 10/19 trials, and none of the control trials (0/18) resulted in instability (P<0.001). Mean treadmill speed (+/-SD) at the onset of instability was 10.8+/-2.5 m/s. Following its onset, nasopharyngeal instability persisted until the end of the treadmill test. This instability, induced by hypoglossal nerve block, produced an expiratory obstruction similar to that seen in a naturally occurring equine disease (dorsal displacement of the soft palate, DDSP) with reduced inspiratory and expiratory pharyngeal pressure and increased expiratory tracheal pressure. These data suggest that stability of the equine upper airway at exercise may be mediated through the hypoglossal nerve. Naturally occurring DDSP in the horse shares a number of anatomic similarities with obstructive sleep apnea. Study of species with extreme respiratory adaptation, such as the horse, may provide insight into respiratory functioning in humans. PMID:19498094

Cheetham, Jonathan; Pigott, John H; Hermanson, John W; Campoy, Luis; Soderholm, Leo V; Thorson, Lisa M; Ducharme, Norm G



Experimental interfascicular nerve grafting.  


Twenty-nine adult rhesus monkeys underwent complete laceration of both tibial nerves at mid-thigh level and repair by different methods to study the relative efficacy of autogenous interfascicular nerve grafts. Sixteen animals in Group I had an interfascicular graft repair using short sural nerve autografts on one limb and fascicular repair without grafts on the other limb. Thirteen animals in Group II, after having a 1-cm segment of tibial nerve resected, had an interfascicular graft repair without tension in one limb and an epineurial repair under moderate tension in the other limb. Evoked nerve and muscle action potentials and muscle strenght in response to repetitive and tetanic stimulation were recorded as baseline values prelaceration and then on re-exploration at 4, 6, 9, or 12 months. All nerves were examined by light and electron microscopy. Electrophysiological data, particularly muscle strength response, showed non-graft repairs to be superior at 4 and 6 months of regeneration. However, by 9 and 12 months the graft repairs had caught up and were equal to the non-graft repairs. Histologically, it was observed that many axons missed the graft segments and were present in extrafascicular connective tissues. Nonetheless, enough axons regenerated to the distal nerve to explain the success of these relatively short grafts. From the results of these experiments, it is concluded that use of autogenous interfascicular grafts offers no advantage over end-to-end non-graft repair. When and end-to-end repair cannot be achieved, use of short interfascicular nerve grafts is feasible and will work. PMID:224152

Bratton, B R; Kline, D G; Coleman, W; Hudson, A R



Traumatic facial nerve injury.  


Facial nerve trauma can be a devastating injury resulting in functional deficits and psychological distress. Deciding on the optimal course of treatment for patients with traumatic facial nerve injuries can be challenging, as there are many critical factors to be considered for each patient. Choosing from the great array of therapeutic options available can become overwhelming to both patients and physicians, and in this article, the authors present a systematic approach to help organize the physician's thought process. PMID:24138740

Lee, Linda N; Lyford-Pike, Sofia; Boahene, Kofi Derek O



Cranial Nerve VIII  

PubMed Central

Cranial nerve VIII brings sound and information about one's position and movement in space into the brain. The auditory and vestibular systems subserve several functions basic to clinical medicine and to psychiatry. This article covers the basics of cranial nerve VIII, hearing and vestibular systems, including common problems with hearing and balance, problems with hearing and balance that tend to be found in psychiatric patients, and some simple assessments of value in clinical practice.

Sanders, Richard D



Spectral and spatial dependence of?diffuse optical signals in response to?peripheral nerve stimulation  

PubMed Central

Using non-invasive, near-infrared spectroscopy we have previously reported optical signals measured at or around peripheral nerves in response to their stimulation. Such optical signals featured amplitudes on the order of 0.1% and peaked about 100 ms after peripheral nerve stimulation in human subjects. Here, we report a study of the spatial and spectral dependence of the optical signals induced by stimulation of the human median and sural nerves, and observe that these optical signals are: (1) unlikely due to either dilation or constriction of blood vessels, (2) not associated with capillary bed hemoglobin, (3) likely due to blood vessel(s) displacement, and (4) unlikely due to fiber-skin optical coupling effects. We conclude that the most probable origin of the optical response to peripheral nerve stimulation is from displacement of blood vessels within the optically probed volume, as a result of muscle twitch in adjacent areas.

Chen, Debbie K.; Erb, M. Kelley; Tong, Yunjie; Yu, Yang; Sassaroli, Angelo; Bergethon, Peter R.; Fantini, Sergio



Crustal displacements due to continental water loading  

NASA Astrophysics Data System (ADS)

The effects of long-wavelength (>100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (?rM) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare ?rM with observed Global Positioning System (GPS) heights (?rO) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the ?rO time series are adjusted by ?rM, their variances are reduced, on average, by an amount equal to the variance of the ?rM. Of the ?rO time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the ?rM. The ?rM time series exhibit long-period variations that could be mistaken for secular tectonic trends or postglacial rebound when observed over a time span of a few years.

van Dam, T.; Wahr, J.; Milly, P. C. D.; Shmakin, A. B.; Blewitt, G.; Lavallée, D.; Larson, K. M.


Increased expression of neuronal nitric oxide synthase in dorsal root ganglion neurons after systemic capsaicin administration  

Microsoft Academic Search

Nitric oxide synthase which is constitutively expressed in some neurons3,8,10,17,20 can be induced in other neurons by pathological conditions.6,15,18,19,21,24,26 For example, sciatic nerve26 or pelvic nerve transection18,21 induced nitric oxide synthase expression in lumbosacral dorsal root ganglion cells. This occurred in small to medium sized dorsal root ganglion neurons suggesting that this change might be limited to, or most prominent

M. A. Vizzard; S. L. Erdman; W. C. De Groat



Hot-solvent miscible displacement  

SciTech Connect

This work describes an experimental and theoretical investigation of miscible displacement under nonisothermal conditions. The hot miscible floods were performed in an adiabatic glass bead pack, displacing one hydrocarbon by a more viscous hydrocarbon, the latter being at an elevated temperature. As a result, dispersion of both mass and heat took place, and was determined by temperature and concentration measurements. The system was simulated by coupled convective-diffusion and thermal conduction-convection equations. The results of the numerical as well as an approximate analytical solution were compared with the experimentally observed behavior. The numerical and experimental results point to the factors which should be considered in the choice of a solvent for a thermal-miscible type oil recovery process.

Awang, M.; Farouq Ali, S.M.



Biomarkers of organophosphorus nerve agent exposure: comparison of phosphylated butyrylcholinesterase and phosphylated albumin after oxime therapy  

Microsoft Academic Search

Organophosphorus nerve agents inhibit the activity of cholinesterases by phosphylation of the active site serine. In addition,\\u000a sarin, cyclosarin, soman and tabun have been shown to phosphylate a tyrosine residue in albumin. Therapies against nerve agent\\u000a poisoning include the use of oximes to reactivate inhibited cholinesterases by displacement of the phosphyl moiety and hence\\u000a detectable levels of adducts with cholinesterases

Robert W. Read; James R. Riches; Jacqueline A. Stevens; Sarah J. Stubbs; Robin M. Black



Knowledge integration and displaced volume  

NSDL National Science Digital Library

This study contrasted spontaneous and reflective knowledge integration instruction delivered using a computer learning environment to enhance understanding of displaced volume. Both forms of instruction provided animated experiments and required students to predict outcomes, observe results, and explain their ideas. In addition, the reflective instruction diagnosed specific inconsistencies in student reasoning and encouraged students to reflect on these dilemmas as well as to construct general principles. We distinguished the impact of instruction on students who believed scientific phenomena are governed by principles (cohesive beliefs) versus students who believed that science is a collection of unrelated ldquofactsrdquo (dissociated beliefs). Students typically held multiple models of displacement, using different explanations depending on the form of assessment. For example, we found that 17% of these middle school students made accurate predictions about displacement experiments prior to instruction and 25% could construct an accurate general principle. However, only 12% consistently used the same explanation across assessments. After instruction, students were more accurate and more consistent: over 50% accurately predicted experimental outcomes, 79% gave an accurate general principle, and about 40% gave consistent responses. We found no advantages for enhanced animations over straightforward animated experiments. The reflective integration instruction led to more substantial long-term changes in student understanding than did spontaneous integration instruction. Furthermore, on a delayed posttest we found that students with cohesive beliefs not only sustained their understanding of displaced volume, but, when exposed to reflective integration instruction, actually continued to construct more predictive views following instruction. In contrast, students with dissociated beliefs made no long-term progress independent of the form of instruction.

Linn, Marcia; Eylon, Bat-Sheva



Refugees and Internally Displaced People  

Microsoft Academic Search

Millions of refugees and internally displaced people (IDP) reflect the human consequences of armed conflicts and disasters\\u000a around the world. These individuals, families, communities, and societies suffer from conditions of war and violence, all\\u000a of which can be considered human rights violations, including torture, rape, abductions, sexual violation, war wounds, deprivation\\u000a of basic needs, ethnic cleansing, persecution and harassment, loss

Nancy Baron; Soeren Buus Jensen; Joop T. V. M. Jong


Noncontact subnanometer measurement of transient surface displacement during action potential propagation  

NASA Astrophysics Data System (ADS)

We have demonstrated non-contact, sub-nanometer optical measurement of neural surface displacement associated with action potential propagation without applying exogenous chemicals or reflection coatings. Signals recorded from crayfish leg nerve using a phase-sensitive optical low coherence reflectometer show that transient neural surface displacement due to action potential propagation is approximately 1 nm in amplitude and 1 ms in duration. Measured optical signals are coincident with electrical action potential arrival to the optical measurement site. Recent experiments indicate signals with similar amplitude and duration are observed in response to repetitive fast stimulation (200 stimuli/s).

Akkin, Taner; Dave, Digant P.; Rylander, H. Grady, III; Milner, Thomas E.



The Displaced Maxillary Canine—a Retrospective Study  

Microsoft Academic Search

\\u000a Abstract\\u000a \\u000a \\u000a Objective:\\u000a   The re-alignment of retained maxillary canines was studied in relation to the degree of displacement in panoramic radiographs,\\u000a mesiodistal root deviations, length of treatment and side-effects. The aim was then to determine whether the decision between\\u000a surgical removal and orthodontic re-alignment can be made on the basis of panoramic radiographs alone.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and Methods:\\u000a   Forty-seven panoramic radiographs with

Torsten Grande; Annemarie Stolze; Heiko Goldbecher; Bärbel Kahl-Nieke



ATP-sensitive potassium currents in rat primary afferent neurons: biophysical, pharmacological properties, and alterations by painful nerve injury  

Microsoft Academic Search

ATP-sensitive potassium (KATP) channels may be linked to mechanisms of pain after nerve injury, but remain under-investigated in primary afferents so far. We therefore characterized these channels in dorsal root ganglion (DRG) neurons, and tested whether they contribute to hyperalgesia after spinal nerve ligation (SNL). We compared KATP channel properties between DRG somata classified by diameter into small or large,

T. Kawano; V. Zoga; J. B. McCallum; H.-E. Wu; G. Gemes; M.-Y. Liang; S. Abram; W.-M. Kwok; Q. H. Hogan; C. D. Sarantopoulos



Genetic impairment of interleukin-1 signaling attenuates neuropathic pain, autotomy, and spontaneous ectopic neuronal activity, following nerve injury in mice  

Microsoft Academic Search

Peripheral nerve injury may lead to neuropathic pain, which is often associated with mechanical and thermal allodynia, ectopic discharge of from injured nerves and from the dorsal root ganglion neurons, and elevated levels of proinflammatory cytokines, particularly interleukin-1 (IL-1). In the present study, we tested the role of IL-1 in neuropathic pain models using two mouse strains impaired in IL-1

Gilly Wolf; Eran Gabay; Michael Tal; Raz Yirmiya; Yehuda Shavit



Acetylcholinesterase-containing nerve cells in the pineal complex and subcommissural area of the frogs, Rana ridibunda and Rana esculenta  

Microsoft Academic Search

In Rana esculenta and Rana ridibunda the frontal organ and the pineal organ (epiphysis cerebri) form a pineal complex. Approximately 60 nerve cells of the frontal organ and 220–320 nerve cells of the pineal organ display a positive acetylcholinesterase reaction (Karnovsky and Roots, 1964). The dorsal wall of the pineal organ is considerably richer in acetylcholinesterase-positive neurons than the ventral

Kenjiro Wake; Manfred Ueck; Andreas Oksche



Acellular Nerve Allografts in Peripheral Nerve Regeneration: A Comparative Study  

PubMed Central

Background Processed nerve allografts offer a promising alternative to nerve autografts in the surgical management of peripheral nerve injuries where short deficits exist. Methods Three established models of acellular nerve allograft (cold-preserved, detergent-processed, and AxoGen® -processed nerve allografts) were compared to nerve isografts and silicone nerve guidance conduits in a 14 mm rat sciatic nerve defect. Results All acellular nerve grafts were superior to silicone nerve conduits in support of nerve regeneration. Detergent-processed allografts were similar to isografts at 6 weeks post-operatively, while AxoGen®-processed and cold-preserved allografts supported significantly fewer regenerating nerve fibers. Measurement of muscle force confirmed that detergent-processed allografts promoted isograft-equivalent levels of motor recovery 16 weeks post-operatively. All acellular allografts promoted greater amounts of motor recovery compared to silicone conduits. Conclusions These findings provide evidence that differential processing for removal of cellular constituents in preparing acellular nerve allografts affects recovery in vivo.

Moore, Amy M.; MacEwan, Matthew; Santosa, Katherine B.; Chenard, Kristofer E.; Ray, Wilson Z.; Hunter, Daniel A.; Mackinnon, Susan E.; Johnson, Philip J.



Nerve globins in invertebrates.  


The expression of nerve hemoglobins in invertebrates is a well-established fact, but this occurrence is uncommon. In the species where nerve globins occur, they probably function as an oxygen store for sustaining activity of the nerves during anoxic conditions. Although invertebrate nerve globins are functionally similar with respect to O2 affinity, they are by no means uniform in structure and can differ in size, cellular localization and heme-coordination. The best-studied nerve globin is the mini-globin of Cerebratulus lacteus, which belongs to a class of globins containing the polar TyrB10/GlnE7 pair in the distal pocket. The amide and phenol side chains normally cause low rates of O2 dissociation and ultra-high O2 affinity by forming strong hydrogen bonds with bound ligands. Cerebratulus hemoglobin, however, has a moderate O2 affinity, due to the presence of a third polar amino-acid in its active site, ThrE11, which inhibits hydrogen bonding to bound oxygen by the B10 tyrosine side chain. PMID:15804828

Geuens, E; Dewilde, S; Hoogewijs, D; Pesce, A; Nienhaus, K; Nienhaus, G U; Olson, J; Vanfleteren, J; Bolognesi, M; Moens, L


High Throughput Screening of Potential Displacer Molecules.  

National Technical Information Service (NTIS)

A bioproduct may be selectively separated from one or more impurities by means of a displacement chromatography system that includes a solvent, a chromatographic resin and a chemically selective displacer. The method includes: dissolving the bioproduct an...

S. M. Cramer K. Rege J. Dordick N. Tugcu



Intrathecal TRESK gene recombinant adenovirus attenuates spared nerve injury-induced neuropathic pain in rats.  


TRESK gene recombinant adenovirus (10 IU/ml), which has been constructed successfully in our previous study, was implemented through an intrathecal injection. The fact that the method can effectively upregulate the expression of TRESK mRNA in the dorsal root ganglia of spared nerve injury in rats was verified. We also investigated the role of TRESK gene recombinant adenovirus in attenuating tactile allodynia and thermal hyperalgesia in spared nerve injury rats. Spared nerve injury to the sciatic nerve induced persistent tactile allodynia, but had no effect on thermal hyperalgesia. Intrathecal injection of TRESK gene recombinant adenovirus (25 µl) into the region of lumbar enlargement in advance reduced tactile allodynia. Moreover, intrathecal injection of TRESK gene recombinant adenovirus (25 µl) significantly alleviated the activation of astrocytes in spinal cord induced by spared nerve injury. The current study shows that an intrathecal injection of the TRESK gene recombinant adenovirus attenuated the activity of astrocytes in spinal cord, which contributed to relieving neuropathic pain in spared nerve injury rats. According to the result reported in our previous study, attenuating the expression of TRESK in dorsal root ganglia was involved in the development of neuropathic pain. On the basis of these results, we theorized that the therapeutic utility of upregulation of TRESK in dorsal root ganglia was effective in relieving neuropathic pain syndromes induced by peripheral nerve injury. PMID:23370493

Zhou, Jun; Yang, Cheng-Xiang; Zhong, Ji-Ying; Wang, Han-Bing



A Spiral Nerve Cuff Electrode for Peripheral Nerve Stimulation  

Microsoft Academic Search

A new type of newe cuff electrode consisting of conduc- tive segments embedded within a self-curling sheath of biocompatihle insulation has been developed. This spiral nerve cuff is biased to self- wrap around peripheral nerves and possesses a \\




Ecological Character Displacement in Adaptive Radiation  

Microsoft Academic Search

I give an overview of the observational and experimental evidence for ecological character displacement in adaptive radiation. Sixty-one published cases of character displacement involving closely related species (congeners) make up the observational data set. All cases involve divergence, even though parallel and convergent dis- placement are theoretically possible. Character ratios in sympatry were greatest when displacement was symmetric (mean 1.54)

Dolph Schluter



Atrioventricular plane displacement in female endurance athletes  

Microsoft Academic Search

WISLØFF, U., J. HELGERUD, A. STØYLEN, and Ø. ELLINGSEN. Atrioventricular plane displacement in female endurance athletes. Med. Sci. Sports Exerc., Vol. 33, No. 9, 2001, pp. 1503-1510. Introduction: A novel hypothesis for increased ventricular pumping describes the heart as a displacement pump, in which atrioventricular plane displacement (AVPD) is an important mechanism. The hypothesis predicts that AVPD increases at high



Burglary Reduction and the Myth of Displacement  

Microsoft Academic Search

Burglary remains a significant crime problem across Australia. While the Australian Institute of Criminology is keen to encourage burglary reduction initiatives, it often encounters the view that targeted operations simply displace crime to another area. This perception of total crime displacement is common, but has no strong evidential basis. While some studies have measured a modest degree of displacement in

Jerry Ratcliffe



Wavelet denoising of displacement estimates in elastography  

Microsoft Academic Search

Wavelet shrinkage denoising of the displacement estimates to reduce noise artefacts, especially at high overlaps in elastography, is presented in this paper. Correlated errors in the displacement estimates increase dramatically with an increase in the overlap between the data segments. These increased correlated errors (due to the increased correlation or similarity between consecutive displacement estimates) generate the so-called “worm” artefact

Udomchai Techavipoo; Tomy Varghese



Cutaneous distribution of zygomaticofacial nerve.  


The aim of this study is to elucidate the cutaneous distribution of the zygomaticofacial nerve (ZFN). Twenty hemifaces of 10 adult Korean cadavers were dissected. ZFN-innervated limits were rectangular and each side was 18.8 +/- 4 mm and 15.8 +/- 3.4 mm. The center of the rectangle was located laterally at 17.3 +/- 5.5 mm from the lateral canthus and then inferiorly at 18.1 +/- 3.1 mm. The cutaneous area innervated by the ZFN was rectangular shaped having a horizontal side that was 9.3 +/- 4% to 27.3 +/- 7.5%of the line from the lateral canthus to the root of helix and a vertical side that was 13.9 +/- 5.8% to 35.7 +/- 5.4% of the line from the lateral canthus to the oral commissure level. Knowledge of ZFN innervation is available with an intraoral approach in maloplasty or midface lift. PMID:17538320

Hwang, Kun; Jin, Sheng; Park, Jun Ho; Chung, In Hyuk



[Peripheral facial nerve palsy].  


Facial palsy can be defined as a decrease in function of the facial nerve, the primary motor nerve of the facial muscles. When the facial palsy is peripheral, it affects both the superior and inferior areas of the face as opposed to central palsies, which affect only the inferior portion. The main cause of peripheral facial palsies is Bell's palsy, which remains a diagnosis of exclusion. The prognosis is good in most cases. In cases with significant cosmetic sequelae, a variety of surgical procedures are available (such as hypoglossal-facial anastomosis, temporalis myoplasty and Tenzel external canthopexy) to rehabilitate facial aesthetics and function. PMID:23627995

Pons, Y; Ukkola-Pons, E; Ballivet de Régloix, S; Champagne, C; Raynal, M; Lepage, P; Kossowski, M



Displacement Current and Surface Flashover  

SciTech Connect

High-voltage vacuum insulator failure is generally due to surface flashover rather than insulator bulk breakdown. Vacuum surface flashover is widely believed to be initiated by a secondary electron emission avalanche along the vacuum-insulator interface. This process requires a physical mechanism to cause secondary electrons emitted from the insulator surface to return to that surface. Here, we show that when an insulator is subjected to a fast high-voltage pulse, the magnetic field due to displacement current through the insulator can provide this mechanism. This indicates the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process.

harris, J R; Caporaso, G J; Blackfield, D; Chen, Y J



An artificial nerve fiber for evaluation of nerve cuff electrodes  

Microsoft Academic Search

The different applications of natural sensors for feedback in rehabilitation systems using functional electrical stimulation (FES) require specialised and optimised designs of nerve cuff electrodes for recording of the sensory information. This paper describes a simple artificial nerve fiber for evaluation of nerve cuff electrode designs, cuff recording configurations and noise reduction methods in a controlled environment. The idea is

Lotte N. S. Andreasen; Johannes J. Struijk; Morten Haugland



Repetitive nerve stimulation for the evaluation of peripheral nerve hyperexcitability  

Microsoft Academic Search

Objective: To examine the utility of repetitive nerve stimulation (RNS) in the evaluation of peripheral nerve hyperexcitability (PNH). Background: PNH describes a group of disorders characterized by muscle cramps, twitching and stiffness. When severe, PNH may be characterized by the presence of continuous muscle fiber activity on routine needle electromyography (EMG). In milder forms of the disease, nerve hyperexcitability may

Michael Benatar; Kristine M Chapman; Seward B Rutkove



Interleukin6 and nerve growth factor levels in peripheral nerve and brainstem after trigeminal nerve injury in the rat  

Microsoft Academic Search

Earlier studies have demonstrated that inflammation plays a role in the development of evoked pain following partial nerve injury. In this report, we demonstrate bilateral changes in interleukin-6 (IL-6) and nerve growth factor (nerve growth factor) levels following unilateral infraorbital nerve (infraorbital nerve) constriction. infraorbital nerve constriction resulted in an initial period of decreased mechanical sensitivity (1 and 3 days),

Leigh C Anderson; Ramesh D Rao



Effects of selective tumor necrosis factor-alpha inhibition to pain-behavioral changes caused by nucleus pulposus-induced damage to the spinal nerve in rats  

Microsoft Academic Search

Application of nucleus pulposus to the spinal nerve and displacement of the adjacent nerve results in behavioral changes in rats. It has been reported that treatment with the tumor necrosis factor-alpha (TNF?) inhibitor, infliximab, significantly reduces spontaneous pain behavior in this animal model. However, there have been no reports of the effects of infliximab on mechanical or thermal hyperalgesia using

Yasuaki Murata; Kjell Olmarker; Ichiro Takahashi; Kazuhisa Takahashi; Björn Rydevik



Roots and Shoots  

NSDL National Science Digital Library

In this outdoor activity, learners discover that plants aren't just shoots (stem, branches, leaves, and flowers) growing above ground, but contain plenty of roots growing undergroundâmore than half the mass of a plant can be its roots. Learners dig up "mystery" plants to investigate their root structures, and match them to different types of root systems. Learners also learn about animals found near plant roots and how humans use roots.

Science, Lawrence H.



Inductive Displacement Sensor for Force Measuring in Humanoid Robotic Application: Testing the Invariance on Angular Displacement  

Microsoft Academic Search

A planar displacement inductive sensor, usable in robotics, is presented in the paper. The sensor is composed of two sensor elements. The first sensor element detects vertical displacement while the second sensor element detects horizontal displacement. Combining information from these two sensor elements, it is possible to determine displacement in a plane. Sensor element is a pair of meander coils.

Snezana M. Djuric; Laszlo Nagy; Mirjana Damnjanovic



Optic nerve hypoplasia in children.  

PubMed Central

Optic nerve hypoplasia (ONH) is characterised by a diminished number of optic nerve fibres in the optic nerve(s) and until recently was thought to be rare. It may be associated with a wide range of other congenital abnormalities. Its pathology, clinical features, and the conditions associated with it are reviewed. Neuroendocrine disorders should be actively sought in any infant or child with bilateral ONH. Early recognition of the disorder may in some cases be life saving. Images

Zeki, S. M.; Dutton, G. N.



Root responses to flooding.  


Soil water-logging and submergence pose a severe threat to plants. Roots are most prone to flooding and the first to suffer from oxygen shortage. Roots are vital for plant function, however, and maintenance of a functional root system upon flooding is essential. Flooding-resistant plants possess a number of adaptations that help maintain oxygen supply to the root. Plants are also capable of initiating organogenesis to replace their original root system with adventitious roots if oxygen supply becomes impossible. This review summarizes current findings on root development and de novo root genesis in response to flooding. PMID:23608517

Sauter, Margret



Optic nerve head segmentation  

Microsoft Academic Search

Reliable and efficient optic disk localization and segmentation are important tasks in automated retinal screening. General-purpose edge detection algorithms often fail to segment the optic disk due to fuzzy boundaries, inconsistent image contrast or missing edge features. This paper presents an algorithm for the localization and segmentation of the optic nerve head boundary in low-resolution images (about 20 ?\\/pixel). Optic

James Lowell; Andrew Hunter; David Steel; Ansu Basu; Robert Ryder; Eric Fletcher; Lee Kennedy



A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.  


Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors' mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors' monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong



Trigeminal Nucleus Caudalis Anatomy: Guidance for Radiofrequency Dorsal Root Entry Zone Lesioning  

Microsoft Academic Search

Object: This study seeks to improve the accuracy of trigeminal nucleus caudalis dorsal root entry zone (DREZ) radiofrequency lesioning by quantifying the size and orientation of the nucleus caudalis. Methods: Using serial axial photographs of 6 formalin-fixed cadaver brainstems, digital nucleus caudalis measurements were taken at 1-mm intervals from the level of the obex to the C2 dorsal nerve roots.

Stephen E. Sandwell; Amr O. El-Naggar; G. Stephen Nettleton; Robert D. Acland



Isolated cranial nerve palsies in multiple sclerosis  

Microsoft Academic Search

During a 10 year period 24 patients with definite multiple sclerosis with isolated cranial nerve palsies were studied (third and fourth nerve: one patient each, sixth nerve: 12 patients, seventh nerve: three patients, eighth nerve: seven patients), in whom cranial nerve palsies were the presenting sign in 14 and the only clinical sign of an exacerbation in 10 patients. MRI

Frank Thömke; Eckart Lensch; Kurt Ringel; Hanns Christian Hopf



Radiation Impairs Perineural Invasion by Modulating the Nerve Microenvironment  

PubMed Central

Purpose Perineural invasion (PNI) by cancer cells is an ominous clinical event that is associated with increased local recurrence and poor prognosis. Although radiation therapy (RT) may be delivered along the course of an invaded nerve, the mechanisms through which radiation may potentially control PNI remain undefined. Experimental Design An in vitro co-culture system of dorsal root ganglia (DRG) and pancreatic cancer cells was used as a model of PNI. An in vivo murine sciatic nerve model was used to study how RT to nerve or cancer affects nerve invasion by cancer. Results Cancer cell invasion of the DRG was partially dependent on DRG secretion of glial-derived neurotrophic factor (GDNF). A single 4 Gy dose of radiation to the DRG alone, cultured with non-radiated cancer cells, significantly inhibited PNI and was associated with decreased GDNF secretion but intact DRG viability. Radiation of cancer cells alone, co-cultured with non-radiated nerves, inhibited PNI through predominantly compromised cancer cell viability. In a murine model of PNI, a single 8 Gy dose of radiation to the sciatic nerve prior to implantation of non-radiated cancer cells resulted in decreased GDNF expression, decreased PNI by imaging and histology, and preservation of sciatic nerve motor function. Conclusions Radiation may impair PNI through not only direct effects on cancer cell viability, but also an independent interruption of paracrine mechanisms underlying PNI. RT modulation of the nerve microenvironment may decrease PNI, and hold significant therapeutic implications for RT dosing and field design for patients with cancers exhibiting PNI.

Bakst, Richard L.; Lee, Nancy; He, Shuangba; Chernichenko, Natalya; Chen, Chun-Hao; Linkov, Gary; Le, H. Carl; Koutcher, Jason; Vakiani, Efsevia; Wong, Richard J.



Mesenchymal stem cells in a polycaprolactone conduit promote sciatic nerve regeneration and sensory neuron survival after nerve injury.  


Despite the fact that the peripheral nervous system is able to regenerate after traumatic injury, the functional outcomes following damage are limited and poor. Bone marrow mesenchymal stem cells (MSCs) are multipotent cells that have been used in studies of peripheral nerve regeneration and have yielded promising results. The aim of this study was to evaluate sciatic nerve regeneration and neuronal survival in mice after nerve transection followed by MSC treatment into a polycaprolactone (PCL) nerve guide. The left sciatic nerve of C57BL/6 mice was transected and the nerve stumps were placed into a biodegradable PCL tube leaving a 3-mm gap between them; the tube was filled with MSCs obtained from GFP+ animals (MSC-treated group) or with a culture medium (Dulbecco's modified Eagle's medium group). Motor function was analyzed according to the sciatic functional index (SFI). After 6 weeks, animals were euthanized, and the regenerated sciatic nerve, the dorsal root ganglion (DRG), the spinal cord, and the gastrocnemius muscle were collected and processed for light and electron microscopy. A quantitative analysis of regenerated nerves showed a significant increase in the number of myelinated fibers in the group that received, within the nerve guide, stem cells. The number of neurons in the DRG was significantly higher in the MSC-treated group, while there was no difference in the number of motor neurons in the spinal cord. We also found higher values of trophic factors expression in MSC-treated groups, especially a nerve growth factor. The SFI revealed a significant improvement in the MSC-treated group. The gastrocnemius muscle showed an increase in weight and in the levels of creatine phosphokinase enzyme, suggesting an improvement of reinnervation and activity in animals that received MSCs. Immunohistochemistry documented that some GFP+ -transplanted cells assumed a Schwann-cell-like phenotype, as evidenced by their expression of the S-100 protein, a Schwann cell marker. Our findings suggest that using a PCL tube filled with MSCs is a good strategy to improve nerve regeneration after a nerve transection in mice. PMID:22646222

Frattini, Flávia; Lopes, Fatima Rosalina Pereira; Almeida, Fernanda Martins; Rodrigues, Rafaela Fintelman; Boldrini, Leonardo Cunha; Tomaz, Marcelo A; Baptista, Abrahão Fontes; Melo, Paulo A; Martinez, Ana Maria Blanco



Neurovascular compression in cranial nerve and systemic disease.  

PubMed Central

As we age, our arteries elongate and our brains "sag." As a consequence of these processes, redundant arterial loops and bridging or intrinsic hindbrain veins may cause cross-compression of cranial nerve root entry zones in the cerebellopontine angle. This pulsatile compression can be seen to produce hyperactive dysfunction of the cranial nerve. Symptoms of trigeminal or glossopharyngeal neuralgia (somatic sensory), hemifacial spasm (somatic motor), tinnitus and vertigo (special sensory) and some cases of "essential" hypertension are caused by these vessels compressing cranial nerves V, IX--X, VII, VIII, and left X and medulla oblongata. Using microsurgical techniques, the symptoms may be relieved by vascular decompression, findings and results in 695 paients are briefly reviewed and correlated. A chronic primate model of "essential" hypertension is briefly described.

Jannetta, P J




Microsoft Academic Search

Certain axons in the abdominal roots and nerve cord of crayfish contain a system of regularly spaced, parallel transverse septa with a periodicity of about 2 µ.Each septum is composed of two roughly parallel membranes, separated by a gap of 150-400 A . The two membranes are frequently fenestrated by pores 550-2000 A in diameter, each occupied by a micro-




Sodium channel expression in the ventral posterolateral nucleus of the thalamus after peripheral nerve injury  

Microsoft Academic Search

Peripheral nerve injury is known to up-regulate the expression of rapidly-repriming Nav1.3 sodium channel within first-order dorsal root ganglion neurons and second-order dorsal horn nociceptive neurons, but it is not known if pain-processing neurons higher along the neuraxis also undergo changes in sodium channel expression. In this study, we hypothesized that after peripheral nerve injury, third-order neurons in the ventral

Peng Zhao; Stephen G Waxman; Bryan C Hains



Delayed loss of spinal motoneurons after peripheral nerve injury in adult rats: a quantitative morphological study  

Microsoft Academic Search

.   The existence of retrograde cell death in sensory dorsal root ganglion (DRG) cells after peripheral nerve injury is well\\u000a established. However, with respect to retrograde motoneuron death after peripheral nerve injury, available data are conflicting.\\u000a This may partly be due to the cell counting techniques used. In the present study, quantitative morphometric methods have\\u000a been used to analyse retrograde

Jianjun Ma; Lev N. Novikov; Mikael Wiberg; Jan-Olof Kellerth



Radiation-induced peripheral nerve neurofibromata in a patient receiving hypofractionated radiation therapy.  


Radiation-induced peripheral nerve tumor, in particular a benign entity such as a neurofibroma, is rare, with only a few cases being reported so far. We demonstrate a case of radiation-induced neurofibromata along the left cervical nerve roots in a man with a background of localized targeted hypofractionated radiation therapy as adjuvant treatment for left cervical nodal metastasis complicating nasopharyngeal carcinoma. The toxicity of high-dose radiation in a hypofractionated regime is also stressed. PMID:18653682

Lai, V; Wong, Y C; Poon, W L; Fu, Y P; Lam, T C; Yuen, S C



An ion displacement membrame model.  


The usual assumption in treating the diffusion of ions in an electric field has been that the movement of each ion is independent of the movement of the others. The resulting equation for diffusion by a succession of spontaneous jumps has been well stated by Parlin and Eyring. This paper will consider one simple case in which a different assumption is reasonable. Diffusion of monovalent positive ions is considered as a series of jumps from one fixed negative site to another. The sites are assumed to be full (electrical neutrality). Interaction occurs by the displacement of one ion by another. An ion leaves a site if and only if another ion, not necessarily of the same species, attempts to occupy the same site. Flux ratios and net fluxes are given as functions of the electrical potential, concentration ratios, and number of sites encountered in crossing the membrane. Quantitative comparisons with observations of Hodgkin and Keynes are presented. PMID:6048876

Hladky, S B; Harris, J D



Variable delivery, fixed displacement pump  


A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

Sommars, Mark F. (Sparland, IL)



Displacement Based Seismic Design Criteria  

SciTech Connect

The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

Costello, J.F.; Hofmayer, C.; Park, Y.J.




SciTech Connect

The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.




[Nerve entrapment syndromes in athletes].  


Sports-related injuries most commonly involve the musculoskeletal system. However, physicians are less familiar with damage to the peripheral nerves attributable to particular sports activities. Nerve entrapment syndromes associated with physical activity may affect all nerves for which entrapment syndromes are known. Peripheral nerve lesions are serious and may delay or preclude the athletes' return to sports, especially in cases with a delayed diagnosis. The aim of the paper is to give an overview of chronic sports-related nerve lesions. Acute nerve injuries are not the focus of this review. A literature search regarding sports-related nerve lesions was conducted. Due to the lack of prospective epidemiological studies, case reports were included (evidence level 4). Nerve entrapment syndromes specific for particular sports activities are described including clinical presentation, diagnostic work-up and treatment. Repetitive and vigorous use or overuse makes the athlete vulnerable to disorders of the peripheral nerves, additionally sports equipment may cause compression of the nerves. The treatment is primarily conservative and includes modification of movements and sports equipment, shoe inserts, splinting, antiphlogistic drugs and local administration of glucocorticoids. Most often cessation of the offending physical activity is necessary. When symptoms are refractory to conservative therapy a referral to surgery is indicated. The outcome of surgical treatment regarding the return of the athlete to competitive sports is not sufficiently investigated in many nerve entrapment -syndromes.This article was primarily published in "Akt Neurol 2012; 6: 292-308". PMID:24030432

Reuter, I; Mehnert, S



Bilateral eventration of sciatic nerve.  


During routine dissection of a 60 years male cadaver, it was observed that the two divisions of sciatic nerve were separate in the gluteal region on both the sides with the tibial nerve passing below the piriformis and the common peroneal nerve piercing the piriformis muscle. The abnormal passage of the sciatic nerve (SN), the common peroneal nerve (CPN), and the tibial nerve (TN), either through the piriformis or below the superior gemellus may facilitate compression of these nerves. Knowledge of such patterns is also important for surgeons dealing with piriformis syndrome which affects 5-6% of patients referred for the treatment of back and leg pain. A high division may also account for frequent failures reported with the popliteal block. PMID:22049898

Sharma, T; Singla, R K; Lalit, M


Water transport across roots  

Microsoft Academic Search

Usually, roots are looked at as rather perfect osmometers with the endodermis being the ‘root membrane’ which is equivalent to the plasma membrane of cells. However, this ‘single-equivalent-membrane model’ of the root does not explain the findings of a variable hydraulic resistance of roots as well as of differences between hydraulic and osmotic water flow and of low reflection coefficients

Ernst Steudle; Lehrstuhl PflanzenOkologie



40 CFR 86.419-2006 - Engine displacement, motorcycle classes.  

Code of Federal Regulations, 2011 CFR

...false Engine displacement, motorcycle classes. 86.419-2006 Section 86.419-2006...419-2006 Engine displacement, motorcycle classes. (a)(1) Engine displacement...b) Motorcycles will be divided into classes based on engine displacement....



Assessing the displacement effects of the Internet  

Microsoft Academic Search

This study examines the ''medium-centric'' and ''user-centric'' approaches in investigating the displacement effects of the Internet. Results from a random sample survey support the ''medium-centric'' approach in displacement effect. The use of the Internet does displace traditional media use of television, newspapers, and radio. The Internet performs a sub- stitutive rather than supplementary function. More important, the use of absolute

Paul S. N. Lee; Louis Leung



Transverse sacral fractures with anterior displacement  

Microsoft Academic Search

Transverse fractures of the sacrum with anterior displacement are the rarest type of transverse sacral fractures. They usually\\u000a occur at the S1–S2 region in suicide jumpers. A clinical study was performed to evaluate the diagnosis, treatment and outcome\\u000a of transverse sacral fractures with anterior displacement. We present six patients with a transverse fracture of the sacrum\\u000a with anterior displacement. All

George S. Sapkas; Andreas F. Mavrogenis; Panayiotis J. Papagelopoulos



Motor nerve lengths of twenty-seven muscles in upper extremity.  


The purpose of this study is to determine the lengths of motor nerves in the upper extremity. Motor nerves of 27 muscles in 10 cadavers (16 extremities) were dissected from their roots at the level of intervertebral foramen to the entry point of the nerves to the corresponding muscles. Distance between acromion and the lateral epicondyle of the humerus was also measured in all cadavers. Nerve length of the coracobrachialis muscle was the shortest (18.26 ± 1.64 cm), while the longest was the nerve of the extensor indicis (59.51 ± 4.80 cm). The biceps brachii, the extensor digitorum communis, and the brachialis muscles showed highest coefficient of variation that makes these nerve lengths of muscles inconsistent about their lengths. This study also offers quotients using division of the lengths of each nerve to acromion-the lateral epicondyle distance. Knowledge of the nerve lengths in the upper extremity may provide a better understanding the reinnervation sequence and the recovery time in the multilevel injuries such as brachial plexus lesions. Quotients may be used to estimate average lengths of nerves of upper extremity in infants and children. Moreover, reliability of the biceps brachii as a determinant factor for surgery in obstetrical brachial plexus lesions should be reconsidered due to its highest variation coefficient. PMID:21898604

Kendir, Simel; Sen, Tülin; Firat, Tüzün; Leblebicio?lu, A Gürsel; Türker, Tolga; Tekdemir, Ibrahim; Elhan, Alaittin



Cranial Nerve II  

PubMed Central

This article contains a brief review of the anatomy of the visual system, a survey of diseases of the retina, optic nerve and lesions of the optic chiasm, and other visual field defects of special interest to the psychiatrist. It also includes a presentation of the corticothalamic mechanisms, differential diagnosis, and various manifestations of visual illusions, and simple and complex visual hallucinations, as well as the differential diagnoses of these various visual phenomena.

Gillig, Paulette Marie; Sanders, Richard D.



Transfection of Nerve Cells  

Microsoft Academic Search

Transfection is a method of transforming cells based on the introduction into living cells of plasmids encoding a particular\\u000a protein or RNA. This review describes the main methods of transfection and considers their advantages and disadvantages. Most\\u000a attention is paid to lentivirus transduction as one of the most efficient methods for transforming nerve cells. The development\\u000a of current transfection systems

S. V. Salozhin; A. P. Bol’shakov



Peripheral Nerve Tumors  

Microsoft Academic Search

\\u000a Peripheral nerve tumors (PNTs) are rare soft tissue lesions that can arise anywhere on the body and as a result have a wide\\u000a differential diagnosis, which is often confirmed to be a PNT only at surgery. PNTs occur both sporadically and within the\\u000a context of genetically predisposing syndromes; hence, a thorough history of the mass and associated symptoms, with a

Joseph Wiley; Asis Kumar Bhattacharyya; Gelareh Zadeh; Patrick Shannon; Abhijit Guha


Permanent Sacral Nerve Stimulation for Fecal Incontinence  

PubMed Central

Objective To characterize the longer-term therapeutic response of permanent sacral nerve stimulation for fecal incontinence and to delineate suitable indications and the mode of action. Summary Background Data A single report of permanent sacral nerve stimulation in three patients followed up for 6 months showed marked improvement in fecal continence. Acute evaluation has shown that the effect may be mediated by altered rectal and anal smooth muscle activity, and facilitation of external sphincter contraction. Methods Five women (age 41–68 years) with fecal incontinence for solid or liquid stool at least once per week were followed up for a median of 16 months after permanent implantation. All had passive incontinence, and three had urge incontinence. The cause was scleroderma in two, primary internal sphincter degeneration in one, diffuse weakness of both sphincters in one, and disruption of both sphincters in one. Results All patients had marked improvement. Urgency resolved in all three patients with this symptom. Passive soiling resolved completely in three and was reduced to minor episodes in two. Continence scores (scale 0–20) improved from a median of 16 before surgery to 2 after surgery. There were no early complications, and there have been no side effects. One patient required wound exploration at 6 months for local pain, and a lead replacement at 12 months for electrode displacement. The quality of life assessment improved in all patients. The resting pressure increased in four patients, but there was no consistent measured physiologic change that could account for the symptomatic improvement. Conclusions In patients with sphincter degeneration and weakness, and possibly in those with sphincter disruption, sacral nerve stimulation markedly improves fecal incontinence.

Malouf, Andrew J.; Vaizey, Carolynne J.; Nicholls, R. John; Kamm, Michael A.



Optic nerve hypoplasia  

PubMed Central

Optic nerve hypoplasia (ONH) is a congenital anomaly of the optic disc that might result in moderate to severe vision loss in children. With a vast number of cases now being reported, the rarity of ONH is obviously now refuted. The major aspects of ophthalmic evaluation of an infant with possible ONH are visual assessment, fundus examination, and visual electrophysiology. Characteristically, the disc is small, there is a peripapillary double-ring sign, vascular tortuosity, and thinning of the nerve fiber layer. A patient with ONH should be assessed for presence of neurologic, radiologic, and endocrine associations. There may be maternal associations like premature births, fetal alcohol syndrome, maternal diabetes. Systemic associations in the child include endocrine abnormalities, developmental delay, cerebral palsy, and seizures. Besides the hypoplastic optic nerve and chiasm, neuroimaging shows abnormalities in ventricles or white- or gray-matter development, septo-optic dysplasia, hydrocephalus, and corpus callosum abnormalities. There is a greater incidence of clinical neurologic abnormalities in patients with bilateral ONH (65%) than patients with unilateral ONH. We present a review on the available literature on the same to urge caution in our clinical practice when dealing with patients with ONH. Fundus photography, ocular coherence tomography, visual field testing, color vision evaluation, neuroimaging, endocrinology consultation with or without genetic testing are helpful in the diagnosis and management of ONH. (Method of search: MEDLINE, PUBMED).

Kaur, Savleen; Jain, Sparshi; Sodhi, Harsimrat B. S.; Rastogi, Anju; Kamlesh



Microbial Adhesion in Flow Displacement Systems  

PubMed Central

Flow displacement systems are superior to many other (static) systems for studying microbial adhesion to surfaces because mass transport and prevailing shear conditions can be adequately controlled and notoriously ill-defined slight rinsing steps to remove so-called “loosely adhering organisms” can be avoided. In this review, we present the basic background required to calculate mass transport and shear rates in flow displacement systems, focusing on the parallel plate flow chamber as an example. Critical features in the design of flow displacement systems are discussed, as well as different strategies for data analysis. Finally, selected examples of working with flow displacement systems are given for diverse biomedical applications.

Busscher, Henk J.; van der Mei, Henny C.



Pulmonary adenocarcinoma metastasis to a dorsal root ganglion: a case report and review of the literature  

PubMed Central

Introduction The dorsal root ganglion is a rare manifestation of metastatic spread. We report what we believe to be the first case of metastasis of a pulmonary adenocarcinoma to the lumbar dorsal root ganglion. Only four descriptions for different primary tumors spreading to the dorsal root ganglion have been described in the literature so far. Case presentation A 70-year-old Caucasian woman with a four-month history of left-sided lumbar radiculopathy was admitted to our department under the assumption of a herniated lumbar disc. Her past medical history included a pulmonary adenocarcinoma and invasive ductal breast cancer. Lumbar magnetic resonance imaging revealed a space-occupying mass in her left neuroforamen L3-L4 with compression of her L3 nerve root. Neurinoma was taken into account as a differential diagnosis, although not considered typical. Surgery revealed a metastasis of pulmonary adenocarcinoma to her dorsal root ganglion. Conclusions Dorsal root ganglion metastases seem to be extremely rare and can mimic primary local nerve sheath tumors. Therefore, they usually present as incidental findings. Resection should be performed strictly under intraoperative monitoring as tumor spread between the nerve fibers is commonly observed. Metastases should be taken into account in spinal nerve tumors involving the dorsal root ganglion, especially in patients harboring known malignant diseases. The low incidence means that no clear treatment advice can be given. Resection is possible under intraoperative monitoring and relieves neurological symptoms.



Recovery of sensory nerve fibres after surgical decompression in lumbar radiculopathy: use of quantitative sensory testing in the exploration of different populations of nerve fibres  

Microsoft Academic Search

Thirty nine patients with unilateral lumbar nerve root compression at one level were examined with quantitative sensory testing immediately before microdiscectomy and at six weeks, four months, and 12 months after surgery. Twenty one healthy volounteers were used as controls. The patients were classified as having a good or a poor result at the one year follow up. The improvement

Ø P Nygaard; R Kloster; S I Mellgren



Neurotrophin releasing single and multiple lumen nerve conduits.  


Tissue engineering strategies for nerve repair employ polymer conduits termed guidance channels and bridges to promote regeneration for peripheral nerve injury and spinal cord injury, respectively. An approach for fabrication of nerve conduits with single and multiple lumens capable of controlled release of neurotrophic factors was developed. These conduits were fabricated from a mixture of poly(lactide-co-glycolide) (PLG) microspheres and porogen (NaCl) that was loaded into a mold and processed by gas foaming. The porosity and mechanical properties of the constructs were regulated by the ratio of porogen to polymer microsphere. The neurotrophin, nerve growth factor (NGF), was incorporated into the conduit by either mixing the protein with microspheres or encapsulating the protein within microspheres prior to gas foaming. A sustained release was observed for at least 42 days, with the release rate controlled by method of incorporation and polymer molecular weight. Released NGF retained its bioactivity, as demonstrated by its ability to stimulate neurite outgrowth from primary dorsal root ganglion (DRG). In vivo results indicate that conduits retain their original architecture, and allow for cellular infiltration into the channels. Polymer conduits with controllable lumen diameters and protein release may enhance nerve regeneration by guiding and stimulating neurite outgrowth. PMID:15911044

Yang, Yang; De Laporte, Laura; Rives, Christopher B; Jang, Jae-Hyung; Lin, Wei-Chun; Shull, Kenneth R; Shea, Lonnie D



Gravitropic bending of cress roots without contact between amyloplasts and complexes of endoplasmic reticulum  

Microsoft Academic Search

The polar arrangement of cell organelles in Lepidium root statocytes is persistently converted to a physical stratification during lateral centrifugation (the centrifugal force acts perpendicular to the root long axis) or by apically directed centrifugation combined with cytochalasin-treatment. Lateral centrifugation (10 min, 60 min at 10\\\\g or 50\\\\g) causes displacement of amylplasts to the centrifugal anticlinal cell wall and shifting

Marina Wendt; Ling-Long Kuo-Huang; Andreas Sievers



Improved Wide Range Expressions for Displacements and Inverse Displacements for Standard Fracture Toughness Specimens.  

National Technical Information Service (NTIS)

Wide range expressions (interpolating polynomials) for displacements for standard ASTM fracture testing specimens have been developed. The strategy for fitting was to fit displacements as a function of crack length for all of the specimens using a similar...

J. A. Kapp



Central condylar displacement with brain abscess from chronic mandibular osteomyelitis.  


In this case report, we describe a unique long-term complication from undiagnosed mandibular osteomyelitis. A 53-year-old female who underwent a dental extraction complicated by chronic postoperative odontogenic infection and cutaneous parotid fistula formation 2 years earlier presented with acute mental status change, gradual unilateral facial nerve palsy (House-Brackmann score V), and nontraumatic dislocation of the condylar head into the middle cranial fossa. The patient's chronic mandibular osteomyelitis led to glenoid fossa erosion, middle cranial fossa penetration, and temporal lobe abscess formation. A combined middle cranial fossa approach through a burr hole placed in the squamous temporal bone near the zygomatic root and intraoral mandibular approach to ipsilateral condylar head was performed to complete partial mandibulectomy, including condylectomy. The patient was treated with 6 weeks of meropenem perioperatively. Four months after the surgery, the patient had complete resolution of skull base osteomyelitis, parotid fistula, and neurologic deficits and full recovery of facial nerve function (House-Brackmann score of I). PMID:23315680

Lee, Thomas; Green, Ross; Hsu, Jack



Effects of ketamine on GABA-evoked excitability of peripheral nerve  

Microsoft Academic Search

The effects of the dissociative anaesthetic, ketamine on GABA-evoked changes in the excitability of myelinated fibers of dorsal and ventral roots of isolated bullfrog sciatic nerves were examined. Ketamine alone (0.01–1000 µM) evoked small increases (10 µM; with ?0.1 µM even larger increases (?10%) were elicited in the ventral root fibers. As well, the increases evoked by ?10 µM ketamine

S. Liske; A. Li; M. E. Morris



Sacral nerve stimulation: Interstim therapy.  


Sacral nerve stimulation is a young but promising technique in the treatment of chronic voiding dysfunctions. Electrical stimulation of the S3 nerve--using a pacemaker device--is able to treat a wide range of pelvic floor dysfunctions. This article gives a brief review on the indications, mechanisms of action and possible complications of this technique. Furthermore, new evolutions in the domain of sacral nerve modulation are discussed. PMID:16288588

Peeren, Frederick; Hoebeke, Piet; Everaert, Karel



Neurophysiology of Nerve Conduction Studies  

Microsoft Academic Search

The methodology for performing standard nerve conduction studies has been established by identifying the most helpful and\\u000a consistent physiological data obtainable while being constrained by a variety of technical and practical limitations. Nerve\\u000a stimulation occurs underneath the negatively charged anode of the applied stimulator and simultaneous hyperpolarization of\\u000a the nerve occurs beneath the positively charged cathode. Referential or bipolar recording

James B. Caress; Gregory J. Esper; Seward B. Rutkove


Land expropriation and displacement in Bangladesh  

Microsoft Academic Search

This paper examines land grabbing in Bangladesh and views such seizures through the lens of displacement and land encroachment. Two different but potentially interacting displacement processes are examined. The first, the char riverine and coastal sediment regions that are in a constant state of formation and erosion, are contested sites ripe for power plays that uproot small producers on their

Shelley Feldman; Charles Geisler




EPA Science Inventory

The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The Block Displacement proce...


Planar inductive sensor for small displacement  

Microsoft Academic Search

This paper presents a meander type displacement inductive sensor, developed in printed circuit board (PCB) technology. It also describes design, realization and the input inductance measurement of sensor. The displacement in two directions (less than 0.5 mm) can be detected by using two sensor's elements (i.e. two pairs of meander coils). In each pair, one of the coils is fixed,

S. Duric; L. Nad; B. Biberdzic; M. Damnjanovic; L. Zivanov



Displacement and Knowledge Construction in Literature Reviews.  

ERIC Educational Resources Information Center

Two literature reviews are interpreted to demonstrate how they are informed by what the author labels the "displacement story," that is, a story of how one prevailing professional paradigm is replaced by another. This study demonstrates how the narration, structure, and language in each review render particular tellings of the displacement story.…

Steinley, Gary


Proceedings of the Displaced Homemakers Conference.  

ERIC Educational Resources Information Center

The 1979 Displaced Homemakers Conference focused on developing awareness of services available from various Illinois agencies to displaced homemakers, generating the spirit and means for cooperative relationships among agencies serving them, and offering prototypes of how women's centers are attempting to coordinate the various services of state…

Illinois State Office of Education, Springfield. Div. of Adult Vocational and Technical Education.


Displacement damage analogs to ionizing radiation effects  

Microsoft Academic Search

We show that concepts, such as effective equivalent dose and the quality factor, which have long been found useful in comparing the effects of different kinds of ionizing radiation, are also applicable in correlating displacement damage effects in semiconductors. In the case of displacement damage, the energy deposition process is determined by the nonionizing energy loss (NIEL), instead of linear

Geoffrey P Summers; Edward A Burke; Michael A Xapsos



Do Dogs (Canis familiaris) Understand Invisible Displacement?  

Microsoft Academic Search

Domestic dogs (Canis familiaris) perform above chance on invisible displacement tasks despite showing few other signs of possessing the necessary representational abilities. Four experiments investigated how dogs find an object that has been hidden in 1 of 3 opaque boxes. Dogs passed the task under a variety of control conditions, but only if the device used to displace the object

Emma Collier-Baker; Joanne M. Davis; Thomas Suddendorf



Bone marrow stromal cells attenuate injury-induced changes in galanin, NPY and NPY Y 1-receptor expression after a sciatic nerve constriction  

Microsoft Academic Search

Single ligature nerve constriction (SLNC) of the rat sciatic nerve triggers neuropathic pain-related behaviors and induces changes in neuropeptide expression in primary afferent neurons. Bone marrow stromal cells (MSCs) injected into the lumbar 4 (L4) dorsal root ganglia (DRGs) of animals subjected to a sciatic nerve SLNC selectively migrate to the other ipsilateral lumbar DRGs (L3, L5 and L6) and

M. F. Coronel; P. L. Musolino; P. R. Brumovsky; T. Hökfelt; M. J. Villar



Nerve conduction and electromyography studies.  


Nerve conduction studies (NCS) and electromyography (EMG), often shortened to 'EMGs', are a useful adjunct to clinical examination of the peripheral nervous system and striated skeletal muscle. NCS provide an efficient and rapid method of quantifying nerve conduction velocity (CV) and the amplitude of both sensory nerve action potentials (SNAPs) and compound motor action potentials (cMAPs). The CV reflects speed of propagation of action potentials, by saltatory conduction, along large myelinated axons in a peripheral nerve. The amplitude of SNAPs is in part determined by the number of axons in a sensory nerve, whilst amplitude of cMAPs reflects integrated function of the motor axons, neuromuscular junction and striated muscle. Repetitive nerve stimulation (RNS) can identify defects of neuromuscular junction (NMJ) transmission, pre- or post-synaptic. Needle EMG examination can detect myopathic changes in muscle and signs of denervation. Combinations of these procedures can establish if motor and/or sensory nerve cell bodies or peripheral nerves are damaged (e.g. motor neuronopathy, sensory ganglionopathy or neuropathy), and also indicate if the primary target is the axon or the myelin sheath (i.e. axonal or demyelinating neuropathies). The distribution of nerve damage can be determined as either generalised, multifocal (mononeuropathy multiplex) or focal. The latter often due to compression at the common entrapment sites (such as the carpal tunnel, Guyon's canal, cubital tunnel, radial groove, fibular head and tarsal tunnel, to name but a few of the reported hundred or so 'entrapment neuropathies'). PMID:22614870

Kane, N M; Oware, A



Nerve Agents: A Comprehensive Review  

Microsoft Academic Search

Nerve agents are perhaps the most feared of potential agents of chemical attack. The authors review the history, physical characteristics, pharmacology, clinical effects, and treatment of these agents.

Sage W. Wiener; Robert S. Hoffman



[Optic nerve neuritis].  


Optic nerve neuritis is one of the most important differential diagnoses of visual loss in young and middle aged adults. The prognosis in terms of functional outcome is generally good. The diagnosis of optic neuritis is clinical. Steroids can reduce the recovery time but do not affect the long-term functional outcome. Magnetic resonance imaging (MRI) is the most important investigation for assessing an associated risk of multiple sclerosis. Optical coherence tomography (OCT) contributes additional details on the course and functional outcome of optic neuritis. In the future OCT may additionally contribute to the relationship between optic neuritis and possible associated multiple sclerosis. PMID:23933792

Steffen, H



Nerve-pulse interactions  

SciTech Connect

Some recent experimental and theoretical results on mechanisms through which individual nerve pulses can interact are reviewed. Three modes of interactions are considered: (1) interaction of pulses as they travel along a single fiber which leads to velocity dispersion; (2) propagation of pairs of pulses through a branching region leading to quantum pulse code transformations; and (3) interaction of pulses on parallel fibers through which they may form a pulse assembly. This notion is analogous to Hebb's concept of a cell assembly, but on a lower level of the neural hierarchy.

Scott, A.C.



Pathological contrast enhancement of the oculomotor and trigeminal nerves caused by intracranial hypotension syndrome.  


The typical symptom of intracranial hypotension syndrome is orthostatic headache. The headache may also be accompanied by neck pain and stiffness, low backache, radicular symptoms, quadriplegia, interscapular pain, nausea/vomiting, and cranial nerve involvement symptoms (hearing and visual problems, face pain and numbness, hypogeusia). Radiologically, on cranial magnetic resonance imaging, intracranial hypotension syndrome is characterized by dural thickening and contrast enhancement, subdural effusion, engorgement of the venous structures, sagging or downward displacement of the brain, and pituitary hyperemia. Although clinical findings related to cranial nerves 3 and 5 have been described in intracranial hypotension, pathological contrast enhancement of these nerves has not. We present a 32-year-old patient whose cranial magnetic resonance imaging shows bilateral pathological contrast enhancement of cranial nerves 3 and 5 and describe a new imaging finding in intracranial hypotension syndrome. PMID:21521210

Albayram, Sait; Asik, Murat; Hasiloglu, Zehra Isik; Dikici, Atilla Suleyman; Erdemli, Halil Eren; Altintas, Ayse



Developmental Changes in Peanut Root Structure during Root Growth and Root-structure Modification by Nodulation  

Microsoft Academic Search

† Background and Aims Basic information about the root and root nodule structure of leguminous crop plants is incomplete, with many aspects remaining unresolved. Peanut (Arachis hypogaea) forms root nodules in a unique process. Structures of various peanut root types were studied with emphasis on insufficiently characterized lateral roots, changes in roots during their ontogenesis and root modification by nodule




In vivo nerve-macrophage interactions following peripheral nerve injury  

PubMed Central

In vertebrates, the peripheral nervous system has retained its regenerative capacity, enabling severed axons to reconnect with their original synaptic targets. While it is well documented that a favorable environment is critical for nerve regeneration, the complex cellular interactions between injured nerves with cells in their environment, as well as the functional significance of these interactions, have not been determined in vivo and in real time. Here we provide the first minute-by-minute account of cellular interactions between laser transected motor nerves and macrophages in live intact zebrafish. We show that macrophages arrive at the lesion site long before axon fragmentation, much earlier than previously thought. Moreover, we find that axon fragmentation triggers macrophage invasion into the nerve to engulf axonal debris, and that delaying nerve fragmentation in a Wlds model does not alter macrophage recruitment but induces a previously unknown ‘nerve scanning’ behavior, suggesting that macrophage recruitment and subsequent nerve invasion are controlled by separate mechanisms. Finally, we demonstrate that macrophage recruitment, thought to be dependent on Schwann cell derived signals, occurs independently of Schwann cells. Thus, live cell imaging defines novel cellular and functional interactions between injured nerves and immune cells.

Rosenberg, Allison; Wolman, Marc A.; Franzini-Armstrong, Clara; Granato, Michael



In vivo nerve-macrophage interactions following peripheral nerve injury.  


In vertebrates, the peripheral nervous system has retained its regenerative capacity, enabling severed axons to reconnect with their original synaptic targets. While it is well documented that a favorable environment is critical for nerve regeneration, the complex cellular interactions between injured nerves with cells in their environment, as well as the functional significance of these interactions, have not been determined in vivo and in real time. Here we provide the first minute-by-minute account of cellular interactions between laser transected motor nerves and macrophages in live intact zebrafish. We show that macrophages arrive at the lesion site long before axon fragmentation, much earlier than previously thought. Moreover, we find that axon fragmentation triggers macrophage invasion into the nerve to engulf axonal debris, and that delaying nerve fragmentation in a Wld(s) model does not alter macrophage recruitment but induces a previously unknown 'nerve scanning' behavior, suggesting that macrophage recruitment and subsequent nerve invasion are controlled by separate mechanisms. Finally, we demonstrate that macrophage recruitment, thought to be dependent on Schwann cell-derived signals, occurs independently of Schwann cells. Thus, live cell imaging defines novel cellular and functional interactions between injured nerves and immune cells. PMID:22423110

Rosenberg, Allison F; Wolman, Marc A; Franzini-Armstrong, Clara; Granato, Michael



The Root Pressure Phenomenon  

ERIC Educational Resources Information Center

Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)

Marsh, A. R.



The Root Pressure Phenomenon  

ERIC Educational Resources Information Center

|Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)|

Marsh, A. R.



Rotor Displacement of the Ultrasonic Motor Having an Angular Displacement Self-Correction Function  

NASA Astrophysics Data System (ADS)

This paper deals with the experimental investigation for confirmation of rotor displacement of the ultrasonic stepping motor having an angular displacement self-correction function. The experiment focused on the relationship between the rotor’s vibration displacement and its staying position for the self-correction. The result proved that the rotor always stays at the position where the displacement is smallest by cutting a slit into the rotor. Moreover, it has also been found that the stable self-correction of rotor angular displacement depends upon both the rotor driving frequency and rotor clamping force.

Chen, Xiaoduo; Kusakabe, Chiharu; Tomikawa, Yoshiro; Takano, Takehiro



Managing Chemotherapy Side Effects: Nerve Changes  


... anD human services national institutes of health Managing Chemotherapy Side Effects Nerve Changes About nerve changes Some chemotherapy can ... from getting cuts, I always wore shoes.” Managing Chemotherapy Side Effects: Nerve Changes Try these tips from others: “Prevent ...



SciTech Connect

I explore the origins of the unphysical predictions from rooted staggered fermion algorithms. Before rooting, the exact chiral symmetry of staggered fermions is a flavored symmetry among the four 'tastes.' The rooting procedure averages over tastes of different chiralities. This averaging forbids the appearance of the correct 't Hooft vertex for the target theory.




Corky root rot  

Technology Transfer Automated Retrieval System (TEKTRAN)

Corky root rot (corchosis) was first reported in Argentina in 1985, but the disease was presumably present long before that. The disease occurs in most alfalfa-growing areas of Argentina but is more common in older stands. In space-planted alfalfa trials scored for root problems, corky root rot was ...


Spatial displacement correlations in polymeric systems  

NASA Astrophysics Data System (ADS)

The spatial correlations of the monomer displacements are studied via molecular-dynamics simulations of a melt of fully flexible, unentangled polymer chains with different length, interacting potential, density, and temperature. Both the scalar and the vector characters of the correlations are considered and their extension quantified in terms of suitable dynamical correlation lengths. Displacements performed at both short, i.e., vibrational, and long times, i.e., comparable to the structural relaxation time, are investigated. On both time scales the spatial correlations are modulated according to the radial distribution function g(r) to an extent which is determined by the character of the correlations, the time scale of the displacements and the structural slowing down. The spatial correlations of the short-time displacements have clear directional character. The modulus correlations of the long-time displacements are more marked, especially for sluggish states. Analogous findings are found by experiments on colloids. By inspecting the dynamical heterogeneities of states with slowed-down dynamics, it is observed that fast monomers exhibit correlations which are stronger and more differing from the bulk than the slow ones. It is shown that states with identical average vibrational monomer displacement exhibit identical spatial correlations of the monomer displacements pertaining to the subsets of the fast and the slow monomers characterizing both the short-time and the long-time dynamical heterogeneities.

Puosi, F.; Leporini, D.



Spatial displacement correlations in polymeric systems.  


The spatial correlations of the monomer displacements are studied via molecular-dynamics simulations of a melt of fully flexible, unentangled polymer chains with different length, interacting potential, density, and temperature. Both the scalar and the vector characters of the correlations are considered and their extension quantified in terms of suitable dynamical correlation lengths. Displacements performed at both short, i.e., vibrational, and long times, i.e., comparable to the structural relaxation time, are investigated. On both time scales the spatial correlations are modulated according to the radial distribution function g(r) to an extent which is determined by the character of the correlations, the time scale of the displacements and the structural slowing down. The spatial correlations of the short-time displacements have clear directional character. The modulus correlations of the long-time displacements are more marked, especially for sluggish states. Analogous findings are found by experiments on colloids. By inspecting the dynamical heterogeneities of states with slowed-down dynamics, it is observed that fast monomers exhibit correlations which are stronger and more differing from the bulk than the slow ones. It is shown that states with identical average vibrational monomer displacement exhibit identical spatial correlations of the monomer displacements pertaining to the subsets of the fast and the slow monomers characterizing both the short-time and the long-time dynamical heterogeneities. PMID:22559500

Puosi, F; Leporini, D



Displacement fields from point cloud data: Application of particle imaging velocimetry to landslide geodesy  

NASA Astrophysics Data System (ADS)

Acquiring spatially continuous ground-surface displacement fields from Terrestrial Laser Scanners (TLS) will allow better understanding of the physical processes governing landslide motion at detailed spatial and temporal scales. Problems arise, however, when estimating continuous displacement fields from TLS point-clouds because reflecting points from sequential scans of moving ground are not defined uniquely, thus repeat TLS surveys typically do not track individual reflectors. Here, we implemented the cross-correlation-based Particle Image Velocimetry (PIV) method to derive a surface deformation field using TLS point-cloud data. We estimated associated errors using the shape of the cross-correlation function and tested the method's performance with synthetic displacements applied to a TLS point cloud. We applied the method to the toe of the episodically active Cleveland Corral Landslide in northern California using TLS data acquired in June 2005-January 2007 and January-May 2010. Estimated displacements ranged from decimeters to several meters and they agreed well with independent measurements at better than 9% root mean squared (RMS) error. For each of the time periods, the method provided a smooth, nearly continuous displacement field that coincides with independently mapped boundaries of the slide and permits further kinematic and mechanical inference. For the 2010 data set, for instance, the PIV-derived displacement field identified a diffuse zone of displacement that preceded by over a month the development of a new lateral shear zone. Additionally, the upslope and downslope displacement gradients delineated by the dense PIV field elucidated the non-rigid behavior of the slide.

Aryal, Arjun; Brooks, Benjamin A.; Reid, Mark E.; Bawden, Gerald W.; Pawlak, Geno R.



Effects of threshold displacement energy on defect production by displacement cascades in ?, ? and ?-LiAlO2  

NASA Astrophysics Data System (ADS)

Threshold displacement energy evaluation and a series of displacement cascade simulations in ?, ?, and ?-LiAlO2 were performed using molecular dynamics. Threshold displacement energy evaluations indicated that higher absolute ionic charge values and larger densities both increase threshold displacement energy. The displacement cascade simulations suggest that the influence of different crystal structures on the number of interstitial atoms generated in a displacement cascade is explainable almost entirely by the difference of the threshold displacement energy.

Tsuchihira, H.; Oda, T.; Tanaka, S.



Functions of the Renal Nerves.  

ERIC Educational Resources Information Center

|Discusses renal neuroanatomy, renal vasculature, renal tubules, renin secretion, renorenal reflexes, and hypertension as related to renal nerve functions. Indicates that high intensitites of renal nerve stimulation have produced alterations in several renal functions. (A chart with various stimulations and resultant renal functions and 10-item,…

Koepke, John P.; DiBona, Gerald F.



Nerve Agent Sensing Biopolymer Wipe.  

National Technical Information Service (NTIS)

This research and development project entitled 'Nerve Agent Sensing Biopolymer Wipe' is directed at developing a simple-to-use enzyme-containing sensor for detecting nerve agent contamination at surfaces, in air and in solution, and to provide a tool for ...

M. Erbeldinger K. LeJeune



Biodegradable fibrin conduit promotes long-term regeneration after peripheral nerve injury in adult rats.  


Peripheral nerve injuries are often associated with loss of nerve tissue and require autologous nerve grafts to provide a physical substrate for axonal growth. Biosynthetic neural conduits could be an alternative treatment strategy in such injuries. The present study investigates the long-term effects of a tubular fibrin conduit on neuronal regeneration, axonal sprouting and recovery of muscle weight following peripheral nerve injury and repair in adult rats. Sciatic axotomy was performed proximally in the thigh to create a 10-mm gap between the nerve stumps. The injury gap was bridged by using a 14-mm-long fibrin glue conduit, entubulating 2 mm of the nerve stump at each end. A reversed autologous nerve graft was used as a control. The regenerative response from sensory and motor neurones was evaluated following retrograde labelling with Fast Blue fluorescent tracer. In control experiments, at 16 weeks following peripheral nerve grafting, 5184 (±574 standard error of mean (SEM)) sensory dorsal root ganglion neurones and 1001 (±37 SEM) spinal motor neurones regenerated across the distal nerve-graft interface. The fibrin conduit promoted regeneration of 60% of sensory neurones and 52% of motor neurones when compared to the control group. The total number of myelinated axons in the distal nerve stump in the fibrin-conduit group reached 86% of the control and the weight of gastrocnemius and soleus muscles recovered to 82% and 89% of the controls, respectively. The present results suggest that a tubular fibrin conduit can be used to promote neuronal regeneration following peripheral nerve injury. PMID:20005193

Pettersson, Jonas; Kalbermatten, Daniel; McGrath, Aleksandra; Novikova, Liudmila N



Point processes and stochastic displacement fields.  


The effect of a stochastic displacement field on a statistically independent point process is analyzed. Stochastic displacement fields can be divided into two large classes: spatially correlated and uncorrelated. For both cases exact transformation equations for the two-point correlation function and the power spectrum of the point process are found, and a detailed study of them with important paradigmatic examples is done. The results are general and in any dimension. Particular attention is devoted to the kind of large-scale correlations that can be introduced by the displacement field and to the realizability of arbitrary "superhomogeneous" point processes. PMID:15697458

Gabrielli, Andrea



Anion-exchange displacement centrifugal partition chromatography.  


Ion-exchange displacement chromatography has been adapted to centrifugal partition chromatography. The use of an ionic liquid, benzalkonium chloride, as a strong anion-exchanger has proven to be efficient for the preparative separation of phenolic acid regioisomers. Multigram quantities of a mixture of three hydroxycinnamic acid isomers were separated using iodide as a displacer. The displacement process was characterized by a trapezoidal profile of analyte concentration in the eluate with narrow transition zones. By taking advantage of the partition rules involved in support-free liquid-liquid chromatography, a numerical separation model is proposed as a tool for preliminary process validation and further optimization. PMID:15516108

Maciuk, Alexandre; Renault, Jean-Hugues; Margraff, Rodolphe; Trébuchet, Philippe; Zèches-Hanrot, Monique; Nuzillard, Jean-Marc



Central migration of neuronal tissue and embryonic stem cells following transplantation along the adult auditory nerve  

Microsoft Academic Search

The regeneration of the auditory nerve remains a challenge in restoring hearing. An interesting approach would be to use a cell replacement therapy with the potential to establish connections from the inner ear to the central auditory system. This hypothesis was tested by xenografted (mouse to rat) implantation of embryonic dorsal root ganglion (DRG) neurons and embryonic stem (ES) cells

Zhengqing Hu; Mats Ulfendahl; N. Petri Olivius



A technique for anodally blocking large nerve fibres through chronically implanted electrodes  

Microsoft Academic Search

If a spinal root of a baboon or rhesus monkey is trapped in an initially loose-fitting silicone rubber channel containing two or more platinum electrodes, electrical pulses sent through these electrodes can stimulate nerve fibres close to the cathode and block the resulting impulses close to the anode. We show (1) how anodal break excitation and excitation of fibres outside

G S Brindley; M D Craggs



Assesing tree-root & soil interaction using pull-out test apparatus  

NASA Astrophysics Data System (ADS)

Knowing in situ root strength provides a better understanding of the responses of tree root systems against external loads. Root pullout devices are used to record these strengths and can be expressed in two ways: pullout force, which is a direct output from the load cell (measured in pounds) or pullout stress, which is the pullout force divided by root cross section area (measured in pounds per square in.). Pullout tests show not only the possible tensile strength of a tree root, but also the interaction between the tree root and the surrounding geological materials. After discussion with engineers from the University of Nottingham-Trent, the U.S. Army Engineer Research and Development Center (ERDC) constructed a root pullout apparatus with some modifications. These modifications included using a T-System configuration at the base of an aluminum frame instead of a diagonal rod and varying the size of the clamp placed around the tested root. The T-System is placed in front of the root perpendicular to the root path. In the ERDC pullout device, the root was pulled directly without a lever system. A string pot was used to measure displacement when the root was pulled. The device is capable of pulling tree roots with a diameter of up to 2.5 in. and a maximum load of 5000 lbs. Using this device, ERDC conducted field operations in Portland, Oregon; Burlington, Washington; and Albuquerque, New Mexico, on Oregon ash, alder, maple, and cedar trees. In general, pullout tests were conducted approximately 60 deg around the tree selected for the tests. The location of a test depended on the availability of a root near the ground surface. A backhoe was used to remove soil around the tree to locate roots. Before the root was secured in a clamp, root diameter was measured and recorded, and the root was photographed. The tree species, dip angle and dip direction of the root, root location with respect to the tree, tree location, dates, weather, and soil type were also recorded. When the test begins the load cell and displacement transducers immediately started recording the measurements, and the measurements are stored on a laptop computer. The hydraulic pump controls the rate of loading for a relatively slow pulling displacement rate of 0.08 in./sec. Failure occurred when the root breaks or was pulled out of the soil. Maximum forces and root failure location were noted, as well as any additional observations during and after the test. In the ERDC tests, root diameters (root with bark) ranged between 0.7 and 2.33 in., the pullout force was between 86 and 3513 lb, and the pullout stress was between 56 and 2645 psi. ERDC recorded three different types of tree-root failures: pure root tensile failure, bonding between root and soil failure, and a combination of the two. In tensile failure, a root breaks abruptly and the force versus displacement curve usually shows a steep slope, and there is no residual strength. In a bonding failure, the force versus displacement curve shows a gentler slope, and there is residual strength. A combined failure mode may also occur. For pullout tests conducted for the ERDC research, the combined mode failure was the most prevalent failure mechanism.

Wibowo, J.; Corcoran, M. K.; Kala, R.; Leavell, D.



Local Structure of Displacively Disordered Pyrochlore Dielectrics  

SciTech Connect

Local cation environments in the pyrochlore dielectrics A{sub 2}B{sub 2}O6O' = (Bi,M){sub 2}(M,Nb){sub 2}O{sub 6}O' (M = Zn, Fe) were determined from the extended X-ray absorption fine structure. The A cations and O' ions are displaced from their ideal positions, yielding the effective (4 + 2 + 2) coordination for the A cations. The A-cation displacements are directed toward a pair of the framework O atoms; the specific displacement directions are determined by the nature of the A cations (i.e., Bi, Zn, Fe) and the local Nb/Zn (or Nb/Fe) B-site configurations. Local correlations among the atomic displacements and both [A{sub 4}O'] and [A{sub 2}B{sub 2}O] configurations provide near-ideal bond valence sums for all constituent species in these pyrochlore structures.

Krayzman,V.; Levin, I.; Woicik, J.



Variance and covariance of accumulated displacement estimates.  


Tracking large deformations in tissue using ultrasound can enable the reconstruction of nonlinear elastic parameters, but poses a challenge to displacement estimation algorithms. Such large deformations have to be broken up into steps, each of which contributes an estimation error to the final accumulated displacement map. The work reported here measured the error variance for single-step and accumulated displacement estimates using one-dimensional numerical simulations of ultrasound echo signals, subjected to tissue strain and electronic noise. The covariance between accumulation steps was also computed. These simulations show that errors due to electronic noise are negatively correlated between steps, and therefore accumulate slowly, whereas errors due to tissue deformation are positively correlated and accumulate quickly. For reasonably low electronic noise levels, the error variance in the accumulated displacement estimates is remarkably constant as a function of step size, but increases with the length of the tracking kernel. PMID:23493610

Bayer, Matthew; Hall, Timothy J



Block Displacement Method Field Demonstration and Specifications.  

National Technical Information Service (NTIS)

The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The...

T. P. Brunsing



Dynamics and Structure of Energetic Displacement Cascades.  

National Technical Information Service (NTIS)

This paper summarizes recent progress in the understanding of energetic displacement cascades and the primary state of damage in metals. On the theoretical side, the availability of supercomputers has greatly enhanced our ability to simulate cascades by m...

R. S. Averback T. Diaz de la Rubia R. Benedek



A resorbable nerve conduit as an alternative to nerve autograft in nerve gap repair  

Microsoft Academic Search

Poly-3-hydroxybutyrate (PHB) occurs within bacterial cytoplasm as granules and is available as bioabsorbable sheets. Previously, the advantage of PHB in primary repair has been investigated while in this study the same material has been used to bridge an irreducible gap. The aim was to assess the level of regeneration in PHB conduits compared to nerve autografts.The rat sciatic nerve was

A. Hazari; M. Wiberg; G. Johansson-Rudén; C. Green; G. Terenghi



Atrophy of the brachialis muscle after a displaced clavicle fracture in an Ironman triathlete: case report.  


Clavicle fractures are frequent injuries in athletes and midshaft clavicle fractures in particular are well-known injuries in Ironman triathletes. In 2000, Auzou et al. described the mechanism leading to an isolated truncular paralysis of the musculocutaneous nerve after a shoulder trauma. It is well-known that nerve palsies can lead to an atrophy of the associated muscle if they persist for months or even longer. In this case report we describe a new case of an Ironman triathlete suffering from a persistent isolated atrophy of the brachialis muscle. The atrophy occurred following a displaced midshaft clavicle fracture acquiring while falling off his bike after hitting a duck during a competition. PMID:21961883

Rüst, Christoph Alexander; Knechtle, Beat; Knechtle, Patrizia; Rosemann, Thomas



Inverted liver with suprahepatic, anteriorly displaced gallbladder.  


A suprahepatic, anteriorly displaced gallbladder in association with an inverted liver is an extremely rare congenital anomaly. We report the clinical and radiologic findings associated with a 78-year-old woman presenting with shortness of breath, desaturation, hypercapnia and hypoxemia. An abnormal chest radiograph demonstrated right hemi-diaphragmatic elevation consistent with a possible eventration. Subsequent imaging by computed tomography (CT) demonstrated an inverted liver with an anteriorly displaced, suprahepatic gallbladder. PMID:20666167

Hibbs, Harold; Ahmad, Usman


The displacement cascade in ceramic oxides  

NASA Astrophysics Data System (ADS)

The displacement cascade in ceramic oxides is studied using the atomic scattering methods of Lindhard et al. and the Monte Carlo TRIM methods of Biersack et al. The results concentrate on the effects of cascade energy and material mass ratio. It is seen that the heavy metal atom is preferentially displaced relative to the lighter O atom and that compositional changes can occur on the scale of the cascade.

Parkin, Don. M.



Polymer displacement in dye-affinity chromatography  

Microsoft Academic Search

Displacement of lactate dehydrogenase from dye-affinity matrices with poly(ethyleneimine) (PEI) was shown to be an effective elution strategy. It resulted in better recoveries and sharper elution profiles than traditional non-specific elution while the purification factors were unchanged. The elution is assumed to proceed via displacement of bound protein by PEI when the polymer binds to the dye-ligands. Complete elution of

Igor Yu. Galaev; Pär Arvidsson; Bo Mattiasson




PubMed Central

The resting and action potentials of the leg nerves of the spider crab are reduced by procaine, cocaine, iodoacetate, KCl, and veratrine. The first three agents depress the sensitivity of the resting potential to anoxia, while the last can be shown to augment it. Glucose sustains activity and the polarized state in the absence of oxygen, an effect blocked by iodoacetate; corresponding concentrations of lactate and pyruvate are inert under most experimental conditions. DDT and veratrine both induce repetitive activity following an impulse, but only the latter does so with a marked increase in negative after-potential. The negative after-potential induced by veratrine is decreased by KCl relatively more than the spike or the resting potential. Elevation of the calcium content of the medium increases this after-potential. Neither ion appreciably alters the time constant of repolarization. The recovery is more rapid than that obtained following prolonged activity of both veratrinized and unveratrinized nerves. Repolarization following a tetanus is accelerated by an increase in the volume of solution in contact with the fibers; associated with this is an augmentation of the positive after-potential which normally follows a bout of activity. Yohimbine induces a positive after-potential following individual spikes which is depressed by an elevation of the potassium or calcium content of the medium. These observations are discussed from the standpoint of the available evidence for the involvement of potassium at the surface of the fibers as regulated by a labile permeability and metabolism. The potassium liberated by the action potential, calculated from the polarization changes, agrees closely with an available analytical figure; less direct observations are also found to be consistent with this view.

Shanes, Abraham M.



Designing ideal conduits for peripheral nerve repair  

PubMed Central

Nerve tubes, guides, or conduits are a promising alternative for autologous nerve graft repair. The first biodegradable empty single lumen or hollow nerve tubes are currently available for clinical use and are being used mostly in the repair of small-diameter nerves with nerve defects of < 3 cm. These nerve tubes are made of different biomaterials using various fabrication techniques. As a result these tubes also differ in physical properties. In addition, several modifications to the common hollow nerve tube (for example, the addition of Schwann cells, growth factors, and internal frameworks) are being investigated that may increase the gap that can be bridged. This combination of chemical, physical, and biological factors has made the design of a nerve conduit into a complex process that demands close collaboration of bioengineers, neuroscientists, and peripheral nerve surgeons. In this article the authors discuss the different steps that are involved in the process of the design of an ideal nerve conduit for peripheral nerve repair.

de Ruiter, Godard C. W.; Malessy, Martijn J. A.; Yaszemski, Michael J.; Windebank, Anthony J.; Spinner, Robert J.



Development and evolution of character displacement.  


Character displacement occurs when competition for either resources or successful reproduction imposes divergent selection on interacting species, causing divergence in traits associated with resource use or reproduction. Here, we describe how character displacement can be mediated either by genetically canalized changes (i.e., changes that reflect allelic or genotype frequency changes) or by phenotypic plasticity. We also discuss how these two mechanisms influence the tempo of character displacement. Specifically, we suggest that, under some conditions, character displacement mediated by phenotypic plasticity might occur more rapidly than that mediated by genetically canalized changes. Finally, we describe how these two mechanisms may act together and determine character displacement's mode, such that it proceeds through an initial phase in which trait divergence is environmentally induced to a later phase in which divergence becomes genetically canalized. This plasticity-first hypothesis predicts that character displacement should be generally mediated by ancestral plasticity and that it will arise similarly in multiple, independently evolving populations. We conclude by highlighting future directions for research that would test these predictions. PMID:22257002

Pfennig, David W; Pfennig, Karin S



Study on optical fiber based displacement sensor  

NASA Astrophysics Data System (ADS)

Fiber optic sensor is commonly used in control and monitoring system for material deformation, strain, temperature, pressure and other industrial process parameters. Fiber optic displacement sensor based on intensity modulation can be designed by using the transmission technique where the intensity gradually changes due to change of detected laser intensity. Previous optical fiber based displacement sensors are constructed using two fibers along with a mirror arrangement or a single optical fiber acting as both transmitter and receiver such as 2X1 fiber couplers. The reported resolution of the system was in the range of 5 ?m-10 ?m. In our present study the displacement sensor composed of a laser source, optical fiber cable, microscope objective and power meter is designed. As in source-fiber coupling geometry, the microscope objective focuses the laser light onto a multimode glass fiber. The other end of the fiber is coupled to a power meter. As the fiber is displaced towards the focused spot, the detected power changes. The displacement resolution of 5 ?m is obtained with this simple setup. In the present paper, the results of theoretical analysis and experimental study of such a simple optical fiber based displacement sensor are presented.

Chakraborty, B.; Sinha, B. K.



Displacement sensor for indoor machine calibrations.  


This paper presents a simple displacement sensor for indoor machine calibrations. The sensor, which is placed in the path of a diverging laser beam, consists of two plane mirror pieces laterally displaced with the line joining their centers initially held perpendicular to the optical axis of the beam during the displacement of the sensor with one of the mirrors always traveling along the optical axis of the laser beam. The optical signals from the two mirrors are combined and a simple detector at the interference plane counts the fringes during the sensor displacement. The sensor could be mounted on the moving head of any mechanical machine, e.g., the lathe machine for displacement calibration. The device has been tested over a range of 10 cm beyond a distance of 150 cm from a diverging laser source giving an accuracy of 1.1015 ?m. Theoretical modeling, simulation, and experimental results are presented which establish that the proposed sensor can be used as a promising displacement measuring device. PMID:23736230

Mudassar, Asloob Ahmad; Butt, Saira



Long-term acrylamide intoxication induces atrophy of dorsal root ganglion A-cells and of myelinated sensory axons.  


We have examined the effects of acrylamide on primary sensory nerve cell bodies and their myelinated axons in chronic acrylamide intoxication. The numbers and sizes of dorsal root ganglion cell bodies (L5) and myelinated nerve fibers were estimated with sterelogical techniques in severely disabled rats which had been treated with 33.3 mg/kg acrylamide twice a week for 7.5 weeks. There was no loss of dorsal root ganglion cells or myelinated nerve fibers in the roots, the sciatic nerve, sural nerve, and a tibial nerve branch. The mean perikaryal volume of A-cells was reduced by 20% (2P < 0.001) from 50000 microm(3) in controls (CV = 0.13) to 40000 microm(3) (0.12), whereas B-cell volume was unchanged. All size-frequency distribution curves of myelinated axon area of peripheral nerves and sensory roots were shifted to the left towards smaller values in rats exposed to acrylamide. In the L5 sensory root 3 mm from the ganglion, there was a significant reduction of mean cross sectional area of myelinated axons by 14% (2P < 0.05) from 7.6 microm(2) (0.11) in controls to 6.5 microm(2) (0.13) in intoxicated rats. The mean cross sectional area of myelinated sural nerve axons was reduced by 22% (2P < 0.001) from 8.6 microm(2) (0.08) in controls to 6.7 microm(2) (0.17) in intoxicated rats. We conclude that chronic intoxication with acrylamide leads to selective atrophy of type A dorsal root ganglion cell bodies and simultaneous atrophy along their peripheral axons, whereas neuronal B-cell bodies and motor axons are spared. It is suggested that the neuronal atrophy might well represent a defect of neurofilament synthesis and transport. PMID:12652090

Tandrup, T; Jakobsen, J



Effects of Carpal Tunnel Release on the Relative Motion of Tendon, Nerve, and Subsynovial Connective Tissue in a Human Cadaver Model  

PubMed Central

Background The purpose of this study was to evaluate the effect of flexor retinaculum division (simulated carpal tunnel release) on the relative motion of flexor tendon, subsynovial connective tissue, and median nerve in human cadaver specimens. Methods Using fluoroscopy, we measured the relative motion of middle finger flexor digitorum superficialis tendon, subsynovial connective tissue, and median nerve in twelve human cadavers with simulated fist motion. Measurements were obtained for three wrist positions: neutral; 60 degrees flexion; and 60 degrees extension. The shear index was defined as the difference in motion between two tissues (tendon, subsynovial connective tissue, or nerve) relative to tendon excursion, expressed as a percentage. After testing with an intact carpal tunnel, the flexor retinaculum was cut and the testing procedure was repeated. Findings With an intact flexor retinaculum, the wrist flexion position showed significantly less displacement for the subsynovial connective tissue and median nerve relative to tendon displacement, and thus the highest potential shear strain between subsynovial connective tissue-tendon, and tendon-nerve. The wrist extension position also had a significantly higher potential shear strain for tendon-nerve compared to the neutral position. After division of the flexor retinaculum, the differences in shear index among wrist positions were reduced. For the wrist flexion position, the subsynovial connective tissue and median nerve displacements significantly increased, indicating lower shear index values. Interpretation These findings suggest that division of flexor retinaculum reduces the potential shear strain and thus possibly the risk of shear injury to tissues with the carpal tunnel.

Yoshii, Yuichi; Zhao, Chunfeng; Henderson, Jacqueline; Zhao, Kristin D.; Zobitz, Mark E.; An, Kai-Nan; Amadio, Peter C.



Stimulation by nerve growth factor of neuropeptide synthesis in the adult rat in vivo: bilateral response to unilateral intraplantar injections  

Microsoft Academic Search

Unilateral intraplantar injections (1\\/day for 3 days) of 4 ?g nerve growth factor (NGF) into the rat hindpaw increased the expression of prepro-tachykinin (PPT)- and prepro-calcitonin gene-related peptide (ppCGRP)-mRNA in bilateral L5 dorsal root ganglia (DRGs). This was accompanied by an increase of CGRP-like immunoreactivity in the ipsi- and contralateral sciatic nerve but by no detectable change of CGRP-IR in

R. Amann; D. J. S. Sirinathsinghji; J. Donnerer; I. Liebmann; R. Schuligoi



Neuron-restrictive silencer factor causes epigenetic silencing of K v4.3 gene after peripheral nerve injury  

Microsoft Academic Search

Peripheral nerve injury causes a variety of alterations in pain-related gene expression in primary afferent, which underlie the neuronal plasticity in neuropathic pain. One of the characteristic alterations is a long-lasting downregulation of voltage-gated potassium (Kv) channel, including Kv4.3, in the dorsal root ganglion (DRG). The present study showed that nerve injury reduces the messenger RNA (mRNA) expression level of

H. Uchida; K. Sasaki; L. Ma; H. Ueda



Sciatic nerve regeneration is not inhibited by anti-NGF antibody treatment in the adult rat.  


Elevated nerve growth factor (NGF) is believed to play a role in many types of pain. An NGF-blocking antibody (muMab 911) has been shown to reduce pain and hyperalgesia in pain models, suggesting a novel therapeutic approach for pain management. Since NGF also plays important roles in peripheral nervous system development and sensory nerve outgrowth, we asked whether anti-NGF antibodies would adversely impact peripheral nerve regeneration. Adult rats underwent a unilateral sciatic nerve crush to transect axons and were subcutaneously dosed weekly for 8weeks with muMab 911 or vehicle beginning 1day prior to injury. Plasma levels of muMab 911 were assessed from blood samples and foot print analysis was used to assess functional recovery. At 8-weeks post-nerve injury, sciatic nerves were prepared for light and electron microscopy. In a separate group, Fluro-Gold was injected subcutaneously at the ankle prior to perfusion, and counts and sizes of retrogradely labeled and unlabeled dorsal root ganglion neurons were obtained. There was no difference in the time course of gait recovery in antibody-treated and vehicle-treated animals. The number of myelinated and nonmyelinated axons was the same in the muMab 911-treated crushed nerves and intact nerves, consistent with observed complete recovery. Treatment with muMab 911 did however result in a small decrease in average cell body size on both the intact and injured sides. These results indicate that muMab 911 did not impair functional recovery or nerve regeneration after nerve injury in adult rats. PMID:23531437

Lankford, K L; Arroyo, E J; Liu, C-N; Somps, C J; Zorbas, M A; Shelton, D L; Evans, M G; Hurst, S I; Kocsis, J D



Restoration of Contralateral Representation in the Mouse Somatosensory Cortex after Crossing Nerve Transfer  

PubMed Central

Avulsion of spinal nerve roots in the brachial plexus (BP) can be repaired by crossing nerve transfer via a nerve graft to connect injured nerve ends to the BP contralateral to the lesioned side. Sensory recovery in these patients suggests that the contralateral primary somatosensory cortex (S1) is activated by afferent inputs that bypassed to the contralateral BP. To confirm this hypothesis, the present study visualized cortical activity after crossing nerve transfer in mice through the use of transcranial flavoprotein fluorescence imaging. In naïve mice, vibratory stimuli applied to the forepaw elicited localized fluorescence responses in the S1 contralateral to the stimulated side, with almost no activity in the ipsilateral S1. Four weeks after crossing nerve transfer, forepaw stimulation in the injured and repaired side resulted in cortical responses only in the S1 ipsilateral to the stimulated side. At eight weeks after crossing nerve transfer, forepaw stimulation resulted in S1 cortical responses of both hemispheres. These cortical responses were abolished by cutting the nerve graft used for repair. Exposure of the ipsilateral S1 to blue laser light suppressed cortical responses in the ipsilateral S1, as well as in the contralateral S1, suggesting that ipsilateral responses propagated to the contralateral S1 via cortico-cortical pathways. Direct high-frequency stimulation of the ipsilateral S1 in combination with forepaw stimulation acutely induced S1 bilateral cortical representation of the forepaw area in naïve mice. Cortical responses in the contralateral S1 after crossing nerve transfer were reduced in cortex-restricted heterotypic GluN1 (NMDAR1) knockout mice. Functional bilateral cortical representation was not clearly observed in genetically manipulated mice with impaired cortico-cortical pathways between S1 of both hemispheres. Taken together, these findings strongly suggest that activity-dependent potentiation of cortico-cortical pathways has a critical role for sensory recovery in patients after crossing nerve transfer.

Yamashita, Haruyoshi; Chen, Shanlin; Komagata, Seiji; Hishida, Ryuichi; Iwasato, Takuji; Itohara, Shigeyoshi; Yagi, Takeshi; Endo, Naoto; Shibata, Minoru; Shibuki, Katsuei



Medical and popular traditions of nerves  

Microsoft Academic Search

We question the assumption that the common complaint of nerves in small Newfoundland fishing villages is a legacy of the late 19th century syndrome called weak nerves or neurasthenia, and instead trace the development of a Western medical science of nerves from the early 1700s to the present. Native descriptions of the physical, especially tonic, nature of nerves and of

Dona Lee Davis; Richard G. Whitten



Bilateral spinal accessory nerve palsy after rhytidectomy  

Microsoft Academic Search

A 64-year-old patient experienced palsy of the right spinal accessory nerve after rhytidectomy. She was evaluated 6 months after surgery for unexplained shoulder pain and weakness since the procedure. Electrophysiological testing showed bilateral spinal nerve palsy without abnormalities in the other shoulder nerves. The electrophysiological findings supported entrapment as the mechanism, rather than nerve section or pure axonal disease due to

Paul Seror; Henri Lellouche



The roots of trees  

NASA Astrophysics Data System (ADS)

The root of a tree develops the twofold function of absorbing water mixed with mineral salts, and anchoring the plant to the substrate. The former activity is the more important in determining the spreading of a root. If, however, the root is regarded only as a bundle of stiffeners implanted in a semi-infinite elastic medium and we want to optimize its shape, then the problem can be reduced to an optimization problem in elasticity.

Villaggio, Piero


Peripheral axotomy increases the expression of galanin message-associated peptide (GMAP) in dorsal root ganglion cells and alters the effects of intrathecal GMAP on the flexor reflex in the rat  

Microsoft Academic Search

We have previously reported that galanin message-associated peptide (GMAP), a fragment of galanin precursor protein, occurs in a limited number of dorsal root ganglion (DRG) cells in rats with intact sciatic nerves. In the present study, the localization of GMAP in dorsal root ganglia, dorsal roots and dorsal horn was analyzed immunohistochemically and compared between rats with intact and sectioned

X.-J Xu; S Andell; X Zhang; Z Wiesenfeld-Hallin; Ü Langel; K Bedecs; T Hökfelt; T Bartfai



Functional Reinnervation of the Canine Bladder after Spinal Root Transection and Immediate End-on-End Repair  

PubMed Central

The goal of this study was to transect and immediately repair ventral roots, selected by their ability to stimulate bladder contraction, to assess the feasibility of bladder reinnervation in a canine model. Brain-derived neurotrophic factor (BDNF) was delivered via an osmotic pump (0.5 or 5 mg/mL) to a cuff surrounding the reanastomosis site to the two root bundles on one side. Electrodes were implanted bilaterally immediately proximal to the site of surgical reanastomosis. Results were compared to four root-intact, control animals that also received bilateral electrode implantation. At 6–12 months post-surgery, five of eight nerve transected and repaired animals showed increased pressure and bladder emptying during electrical stimulation of the repaired ventral roots contralateral to the BDNF delivery side. Nerve tracing studies one year postoperatively determined the repaired roots to be S1 and S2 and showed regrowth of axons from the spinal cord to nerve sites proximal to the repair site and to the bladder, and the presence of neurofilament-labeled axons growing across the ventral root repair site. In conclusion, transected ventral and dorsal roots in the sacral spine can be repaired and are capable of functionally reinnervating the urinary bladder. This feasibility study paves the way for future studies utilizing other more proximal motor nerves to bypass the transection site for bladder reinnervation.




Bilateral peripheral neural activity observed in vivo following unilateral nerve injury  

PubMed Central

Manganese-enhanced magnetic resonance imaging (MRI) is a surrogate method to measure calcium content in nervous system since manganese physiologically follows calcium. Manganese is detectable in MRI and therefore visualizes structures and cell populations that actively regulate calcium. Since calcium is actively recruited for the transmission of action potentials, our purpose is to validate manganese-enhanced MRI for detection of changes in lumbar nerves related to nociception. A neuropathic pain model was created by chronic constrictive injury of the left sciatic nerve of Sprague-Dawley rats. Behavioral measurements, using von Frey’s tests, confirmed the presence of significant allodynia in the left hind limb of animals in the injured group. T1-weighted fast spin echo images were obtained of the lumbar cord and plexus of animals with injured left sciatic nerve and uninjured animals (control) scanned in a 7 Tesla magnet after intraperitoneal manganese chloride administration four weeks after surgery. Lumbar nerve roots and sciatic nerves in the injured group show increased normalized manganese-enhanced MRI signal, representing manganese enhancement, compared to the control group. In conclusion, animals with neuropathic pain in the left hind limb show increased manganese uptake in not only the injured sciatic nerve but also in the contralateral uninjured sciatic nerve on manganese-enhanced MRI in vivo. Although poorly understood, this finding corroborates ex vivo finding of bilateral nociceptive-related molecular changes in the nervous system of unilateral pain models.

Behera, Deepak; Behera, Subrat; Jacobs, Kathleen E; Biswal, Sandip



[The ulnar nerve compression syndrome].  


The ulnar nerve has to bear a large amount of compression, especially in the cubital tunnel, which can be deducted from the topographic relation of this nerve to the elbow. Apart from tightness of the tunnel, intraarticular changes can also cause compression of the nerve. A further narrow tunnel in the course of the ulnar nerve is the "loge de GUYON", situated in the hypothenar region. A careful neurological examination of sensory and motor signs as well as an accurate electromyographical examination differentiate compression syndromes from other neuropathies. Two unusual cases of a functional cubital tunnel syndrome are demonstrated: their cause was primarily a chondromatosis of the elbow joint in one case a functional vasal compression in the other case. PMID:7250791

Thümler, P; Goymann, V



Ion Channels in Nerve Membranes  

ERIC Educational Resources Information Center

Discusses research that indicates that nerve membranes, which play a key role in the conduction of impulses, are traversed by protein channels with ion pathways opened and closed by the membrane electric field. (Author/MLH)

Ehrenstein, Gerald



Ion Channels in Nerve Membranes  

ERIC Educational Resources Information Center

|Discusses research that indicates that nerve membranes, which play a key role in the conduction of impulses, are traversed by protein channels with ion pathways opened and closed by the membrane electric field. (Author/MLH)|

Ehrenstein, Gerald



[Nerve-sparing radical prostatectomy].  


The neuroanatomy of the pelvic space was studied in order to clarify the course of cavernous nerves responsible for erectile function. The cavernous nerves travel along the dorsolateral portion at the base toward the apex of the prostate, then penetrate urogenital diaphragm at the lateral aspect of the membranous urethra. According to the anatomical findings, nerve-sparing radical prostatectomy was performed through the antegrade approach in 28 patients with prostate cancer. No significant surgical complications were encountered in the present series. Of the 28, evaluable cases were limited to 22 in terms of erection. Fifteen patients (68%) recovered their erectile function after nerve-sparing surgery. Therefore, the present surgical technique seems to be effective for the preservation of male sexual function following radical pelvic surgery. PMID:3382190

Okada, K; Tada, M; Nakano, A; Konno, T



Bone Augmentation and Nerve Repositioning  


... Types of Bone-Augmentation Procedures Nerve Repositioning For dental implants to be successful, the jawbone must have enough ... of procedures used to "build" bone so that dental implants can be placed. These procedures typically involve grafting ( ...


Nerve Disease and Bladder Control  


... signals from the brain to the bladder and sphincter. Overactive bladder. Damaged nerves may send signals to ... sudden, strong urge to urinate Poor control of sphincter muscles. Sphincter muscles surround the urethra and keep ...


Inefficiency of upward displacement operating theatre ventilation.  


A new thermally based ventilation system ('Floormaster') with inlet of cool clean air at floor level, and evacuation at the ceiling of the air warmed by activity in the room (upward displacement ventilation, 17 air changes/h) was compared with a standard positive pressure (plenum) ventilation system with air supply through an inclined perforated screen along one wall at the ceiling and evacuation at floor level (conventional turbulent or mixing system, 16 air changes/h). The study was made during rigidly standardized sham operations (N = 20) performed in the same operating room by a six-member team wearing non-woven disposable or cotton clothing. In general the upward displacement system removed dust particles too small to carry bacteria (0.16-<0.3 microm, 0.001displacement system also yielded two to threefold higher air and surface bacterial counts in areas important for surgical asepsis (wound area, instrument table) especially with regard to bacterial sedimentation (0.001displacement system was insufficient elimination of the larger bacteria-carrying particles. The type of clothing worn by the members of the team did not influence the overall results. We conclude that an upward displacement system will lead to increased counts of airborne and sedimenting bacteria and thus increase the risk of postoperative infection in comparison with conventional operating room ventilation systems. PMID:8999051

Friberg, B; Friberg, S; Burman, L G; Lundholm, R; Ostensson, R



Position of dorsal root ganglia in the lumbosacral region in patients with radiculopathy  

PubMed Central

Background When applying pulsed radiofrequency on dorsal root ganglia for treating chronic lower back pain, maximum efficiency can be expected when a needle is placed 1-2 cm peripheral to the dorsal root ganglion. The object of this study is to analyze images taken after adding contrast to transforaminal epidural injection, categorize root ganglia according to anatomical position, and provide a reference for efficient needle positioning in applying pulsed radiofrequency on dorsal root ganglia. Methods From January 2008 to January 2009, 457 patients who visited our hospital for root pain or radiculopathy were treated with transforaminal epidural injection on the nerve roots based on the dermatome of the painful area. Anteroposterior views were taken after injection of contrast. A virtual line was made by connecting the internal and external parts of the spinal pedicle from the contrast images. Then the dorsal root ganglia were categorized as intraspinal (IS), intraforaminal (IF), or extraforaminal (EF). Results In the fourth lumbar spine, dorsal root ganglia positions were 48% IF, 41% IS, and 6% EF. In the fifth lumbar spine, dorsal root ganglia positions were 75% IF, 10% IS, and 6% EF. In the first sacral spine, dorsal root ganglia locations were 8% IF and 83% IS. Conclusions Positional categorization of dorsal root ganglia according to contrast images was proven to be good anatomical references for effective radiofrequency or blocking of dorsal root ganglia.

Moon, Hyun Seog; Kim, Yeon Dong; Song, Bang Hoon; Cha, Young Deog; Song, Jang Ho



Frictional behavior of large displacement experimental faults  

USGS Publications Warehouse

The coefficient of friction and velocity dependence of friction of initially bare surfaces and 1-mm-thick simulated fault gouges (400 mm at 25??C and 25 MPa normal stress. Steady state negative friction velocity dependence and a steady state fault zone microstructure are achieved after ???18 mm displacement, and an approximately constant strength is reached after a few tens of millimeters of sliding on initially bare surfaces. Simulated fault gouges show a large but systematic variation of friction, velocity dependence of friction, dilatancy, and degree of localization with displacement. At short displacement (<10 mm), simulated gouge is strong, velocity strengthening and changes in sliding velocity are accompanied by relatively large changes in dilatancy rate. With continued displacement, simulated gouges become progressively weaker and less velocity strengthening, the velocity dependence of dilatancy rate decreases, and deformation becomes localized into a narrow basal shear which at its most localized is observed to be velocity weakening. With subsequent displacement, the fault restrengthens, returns to velocity strengthening, or to velocity neutral, the velocity dependence of dilatancy rate becomes larger, and deformation becomes distributed. Correlation of friction, velocity dependence of friction and of dilatancy rate, and degree of localization at all displacements in simulated gouge suggest that all quantities are interrelated. The observations do not distinguish the independent variables but suggest that the degree of localization is controlled by the fault strength, not by the friction velocity dependence. The friction velocity dependence and velocity dependence of dilatancy rate can be used as qualitative measures of the degree of localization in simulated gouge, in agreement with previous studies. Theory equating the friction velocity dependence of simulated gouge to the sum of the friction velocity dependence of bare surfaces and the velocity dependence of dilatancy rate of simulated gouge fails to quantitatively account for the experimental observations.

Beeler, N. M.; Tullis, T. E.; Blanpied, M. L.; Weeks, J. D.



Nerve conduction during Wallerian degeneration in the baboon  

Microsoft Academic Search

Conduction in the lateral popliteal nerve of the baboon was studied during the course of Wallerian degeneration. Six nerves were examined. In each case the muscle response to nerve stimulation and the ascending nerve action potential were recorded daily until the nerve became inexcitable. The muscle response to nerve stimulation disappeared after four to five days, but ascending nerve action

R. W. Gilliatt; R. J. Hjorth



Atomistic Simulation of Displacement Cascades in Zircon  

SciTech Connect

Low energy displacement cascades in zircon (ZrSiO4) initiated by a Zr primary knock-on atom have been investigated by molecular dynamics simulations using a Coulombic model for long-range interactions, Buckingham potential for short-range interactions and Ziegler-Biersack potentials for close pair interactions. Displacements were found to occur mainly in the O sublattice, and O replacements by a ring mechanism were predominant. Clusters containing Si interstitials bridged by O interstitials, vacancy clusters and anti-site defects were found to occur. This Si-O-Si bridging is considerable in quenched liquid ZrSiO4.

Devanathan, Ram; Weber, William J.; Corrales, Louis R.; BP McGrail and GA Cragnolino



Displacement sensors using soft magnetostrictive alloys  

SciTech Connect

The authors report results on the response of a family of displacement sensors, which are based on the magnetostrictive delay line (MDL) technique, using current conductor orthogonal to the MDL. Such sensing technique is based on the change of the magnetic circuit and the acoustic stress point of origin due to the displacement of a soft magnetic material above it. Integrated arrays of sensors can be obtained due to the acoustic delay line technique and they can be used as tactile arrays, digitizers or devices for medical application (gait analysis etc.), while absence of hysteresis and low cost of manufacturing make them competent in this sector of sensor market.

Hristoforou, E. (NCSR Demokritos Aghia Paraskevi, Athens (Greece). Inst. of Material Science); Reilly, R.E. (King's College London (United Kingdom). Electronic and Electrical Engineering Dept.)



Jozef Zwislocki: Impact on models of coding in the auditory nerve  

NASA Astrophysics Data System (ADS)

The auditory nerve has long been considered a window on the biophysical mechanisms of cochlear transduction and the most carefully characterized aspect of the responses of single auditory-nerve fibers has been the tuning curve. Perhaps the most intensively studied question in auditory theory is: What is the relationship between the shapes of these tuning curves and basilar membrane displacements? The basilar membrane measurements of Georg von Bekesy stimulated a generation of basilar-membrane modelers, none more notable than Joe Zwislocki, who was awarded the first von Bekesy Medal by the Acoustical Society in 1985. The impact of Zwislocki's basilar membrane models on our understanding of auditory nerve tuning will be reviewed. The properties of auditory-nerve discharge patterns are also shaped by the filtering properties of the hair cell/synapse complex. The major contributions of Joe and his students to our understanding of this filtering through their elegant experimental and modeling studies of adaptation in the auditory nerve will be presented. Throughout his career, Joe Zwislocki has maintained an active interest in loudness summation and his work in relating the input/output characteristics of auditory-nerve fibers to loudness will be highlighted.

Sachs, Murray B.



A Bibliography on Nerve Conduction and Nerve Impulses (Rand Library Literature Search No. 127).  

National Technical Information Service (NTIS)

The bibliography is concerned with the behavior of networks of nerve cells. Emphasis is placed on waves of nerve impulses passing through masses of nerve tissue, excluding 'brain waves' (EEG). The bibliography does not include items dealing with automata ...

E. McKeldin L. Newman J. Wallach



Meniscus root repair.  


Root tears are a subset of meniscal injuries that result in significant knee joint pathology. Occurring on either the medial or lateral side, root tears are defined as radial tears or avulsions of the posterior horn attachment to bone. After a root tear, there is a significant increase in tibio-femoral contact pressure concomitant with altered knee joint kinematics. Previous cadaver studies from our institution have shown that root repair of the medial meniscus is successful in restoring joint biomechanics to within normal limits. Indications for operative management of meniscal root tears include (1) a symptomatic medial meniscus root tear with minimal arthritis and having failed non-operative treatment, and (2) a lateral root tear in associated with an ACL tear. In this review, we describe diagnosis, imaging, patient selection, and arthroscopic surgical technique of medial and lateral meniscus root injuries. In addition we highlight the pearls of repair technique, associated complications, post-operative rehabilitation regimen, and expected outcomes. PMID:22555205

Vyas, Dharmesh; Harner, Christopher D



Seeds: Roots and Shoots  

NSDL National Science Digital Library

In this indepth hands-on activity, learners build a structure that allows them to observe the growth of roots and the correlation between root growth and stem extension. Because no dirt is used in this arrangement, a guiding question can be posed: What does the plant need to grow? The PDF includes activity rationale, procedure, background and follow-up discussion suggestions.

Education Development Center, Inc.




Microsoft Academic Search

SUMMARY A method is described which, although not considered commercially practical, proved to be very successful in rooting cuttings of Guatemalan avocado varieties. Essentially it consists of obtaining cuttings from stems, the bases of which have at no time been exposed to light or low humidity. In certain experimental work with the avocado, own rooted trees, that is trees propagated

E. F. Frolich


Aortic root replacement  

Microsoft Academic Search

Between September 1976 and September 1993, 270 patients underwent aortic root replacement at our institution. Two hundred fifty-two patients underwent a Bentall composite graft repair and 18 patients received a cryopreserved homograft aortic root. One hundred eighty-seven patients had a Marfan aneurysm of the ascending aorta (41 with dissection) and 53 patients had an aneurysm resulting from nonspecific medial degeneration

Vincent L. Gott; A. Marc Gillinov; Reed E. Pyeritz; Duke E. Cameron; Bruce A. Reitz; Peter S. Greene; Christopher D. Stone; Robert L. Ferris; Diane E. Alejo; Victor A. McKusick



Axial differences in the reinnervation of the goldfish optic tectum by regenerating optic nerve fibres  

Microsoft Academic Search

1.In adult goldfish the caudal half of the optic tectum was removed. In some animals the corresponding optic nerve was crushed as well. The animals were later used to map the retinotectal projection.2.In fishes with the tectal lesion only, the displaced projection from the missing half-tectum was found to be partially restored over the residual rostral half-tectum, in appropriate retinotopic

R. M. Gaze; S. C. Sharma



Plane displacement measurement of rigid body by laser speckle  

NASA Astrophysics Data System (ADS)

A measurement system of plane displacement in rigid body was designed. Plane displacement was calculated by the cross-correlation of speckle image. Measurement results showed that the absolute-error and the opposite-error of the plane displacement less than +/-14?m and +/-6.25% respectively, under the displacement range of 300?m.

Zhong, Chuan; Shen, Changyu; Lin, Zhaoxiang; Li, Ke



Plane displacement measurement of rigid body by laser speckle  

Microsoft Academic Search

A measurement system of plane displacement in rigid body was designed. Plane displacement was calculated by the cross-correlation of speckle image. Measurement results showed that the absolute-error and the opposite-error of the plane displacement less than +\\/-14mum and +\\/-6.25% respectively, under the displacement range of 300mum.

Chuan Zhong; Changyu Shen; Zhaoxiang Lin; Ke Li



Plane displacement measurement of rigid body by laser speckle  

Microsoft Academic Search

A measurement system of plane displacement in rigid body was designed. Plane displacement was calculated by the cross-correlation of speckle image. Measurement results showed that the absolute-error and the opposite-error of the plane displacement less than ±14 ?m and ±6.25% respectively, under the displacement range of 300 ?m.

Chuan Zhong; Changyu Shen; Linzhao Xiang; Ke Li



Displacement of organelles in plant gravireceptor cells by vibrational forces and ultrasound.  

NASA Astrophysics Data System (ADS)

Plant gravity perception can be studied by displacing statoliths inside receptor cells by forces other than gravity. Due to mechanical heterogeneity of statocytes various ponderomotive forces can be used for this purpose. In a plant subjected to non- symmetric vibrations statoliths experience inertial force proportional to the difference between their density and that of cytoplasm and to the instantaneous acceleration of the cell. This force causes cyclic motion of statoliths relative to cytoplasm and, depending on the profile of oscillations, can result in a net displacement of them (due to complex rheology of the cell interior), similar to sedimentation. This can be described as "vibrational" ponderomotive force acting on the statoliths. Vertically growing Arabidopsis seedlings, subjected to horizontal, sawtooth shaped oscillations (250 Hz, 1.5 mm amplitude), showed 17+/-2o root curvature toward and shoot curvature of 11+/-3o against the stronger acceleration. When the polarity of the oscillations was reversed, the direction of curvature of shoots and roots was also reversed. Control experiments with starchless mutants (TC7) produced no net curvature, which indicates that dense starch-filled amyloplasts are needed for the effect. These control experiments also eliminate touch-induced reactions or other side-effects as the cause of the curvature. Linum roots curved 25+/-7o . Ceratodon protonemata subjected to the same oscillations have shown displacement of plastids and curvature consistent with the pattern observed during graviresponse: positively gravitropic wwr mutant curved in the direction of the plastid displacement, WT curved in the opposite direction. Acoustic ponderomotive forces, originating from transfer of a sonic beam momentum to the medium due to sound scattering and attenuation in a mechanically heterogeneous system, also can displace statoliths. Vertical flax seedlings curved away from the ultrasonic source (800 kHz, 0.1 W/cm2 ) presumably as a reaction to amyloplasts displacement by acoustic forces. Besides investigating the graviperception mechanism, vibrational and acoustic forces can serve as tools for analyzing mechanical properties of cell interior. Practical applications of this technology could include providing directional stimuli for plants in microgravity by low doses of vibrations. Vibrations present on board of spacecraft may have vectorial effects on plants and other organisms, and their influence should be assessed.

Kuznetsov, O.; Nechitailo, G.; Kuznetsov, A.


Spatial characterization of root reinforcement at stand scale: Theory and case study  

NASA Astrophysics Data System (ADS)

We propose a new upscaling approach for quantify root reinforcement at the stand scale using the spatially explicit root bundle model (RBM) for describing pullout force-displacement behavior coupled with a model for lateral root distribution. The root distribution model was calibrated using data of two excavated soil profiles, and validated with measurements of root distribution along the scarp of an artificially rainfall-triggered landslide in a vegetated hillslope above the Rhine river in northern Switzerland. Results show that the model overestimates small root density (1-3 mm diameter), leading to an error in estimated maximum root reinforcement of about 28%. For comparison, the most commonly used model of Wu overpredicts root reinforcement by a factor of 3. The spatial variability of estimated maximum root reinforcement within the forest stand is high, ranging from 0 to 20 kPa. Most soil reinforcement by roots occurs close to the tree stem or in zones where root systems overlap. The new approach provides a detailed description of maximum root reinforcement on a slope, an essential element for the prediction of shallow landslides and the management of protection forests.

Schwarz, M.; Cohen, D.; Or, D.



Intermuscular lipoma of the gluteus muscles compressing the sciatic nerve: an inverted sciatic hernia.  


The authors report the case of a 50-year-old woman with a benign intermuscular lipoma of the gluteus compressing the sciatic nerve in its course through the sciatic notch. This benign soft-tissue tumor extended into the pelvis, displacing the rectum laterally. Resection was necessary to alleviate symptoms and prevent irreversible damage of the nerve. Wide exposure of the piriformis muscle and sciatic nerve via a transgluteal approach allowed safe lesion removal, and thus avoiding a laparotomy to resect the intrapelvic extension of the tumor. This report features a curious case of soft-tissue tumor growth across the sciatic foramen forming an inverted sciatic hernia. The authors' proposed approach was simple and safe and avoided a laparotomy. PMID:22900844

López-Tomassetti Fernández, Eudaldo M; Hernández, Juan Ramón Hernández; Esparragon, Jose Ceballos; García, Angel Turegano; Jorge, Valentin Nuñez



Humeral trochlear hypoplasia secondary to epiphyseal injury as a cause of ulnar nerve palsy.  


Humeral trochlear hypoplasia (HTH) is a rare condition that occasionally results in ulnar nerve palsy. A 41-year-old man developed HTH secondary to an epiphyseal injury of the trochlea incurred 33 years earlier. This may be the first report of a case of HTH caused by injury. The ulnar nerve appeared compressed by the malposition of the HTH against the medial head of the triceps brachii when the joint was flexed. The close proximity of the olecranon to the HTH also allowed the triceps brachii muscle to compress the nerve by displacing medially and overriding the bone. The condition was resolved surgically and the patient returned to his former occupation as a coal miner. PMID:2830073

Minami, A; Sugawara, M



Insect Wing Displacement Measurement Using Digital Holography  

SciTech Connect

Insects in flight have been studied with optical non destructive techniques with the purpose of using meaningful results in aerodynamics. With the availability of high resolution and large dynamic range CCD sensors the so called interferometric digital holographic technique was used to measure the surface displacement of in flight insect wings, such as butterflies. The wings were illuminated with a continuous wave Verdi laser at 532 nm, and observed with a CCD Pixelfly camera that acquire images at a rate of 11.5 frames per second at a resolution of 1392x1024 pixels and 12 Bit dynamic range. At this frame rate digital holograms of the wings were captured and processed in the usual manner, namely, each individual hologram is Fourier processed in order to find the amplitude and phase corresponding to the digital hologram. The wings displacement is obtained when subtraction between two digital holograms is performed for two different wings position, a feature applied to all consecutive frames recorded. The result of subtracting is seen as a wrapped phase fringe pattern directly related to the wing displacement. The experimental data for different butterfly flying conditions and exposure times are shown as wire mesh plots in a movie of the wings displacement.

Aguayo, Daniel D.; Mendoza Santoyo, Fernando; Torre I, Manuel H. de la; Caloca Mendez, Cristian I. [Centro de Investigaciones en Optica A. C., Loma del Bosque 115, Lomas del Campestre, Leon, Guanajuato, Mexico 37150 (Mexico)



Stability of Helium Clusters during Displacement Cascades  

SciTech Connect

The interaction of displacement cascades with helium-vacancy clusters is investigated using molecular dynamics simulations. The He-vacancy clusters initially consist of 20 vacancies with a Helium-to-vacancy ratio ranging from 0.2 to 3. The primary knock-on atom (PKA) energy, Ep, varies from 2 keV to 10 keV, and the PKA direction is chosen such that a displacement cascade is able to directly interact with a helium-vacancy cluster. The simulation results show that the effect of displacement cascades on a helium-vacancy cluster strongly depends on both the helium-to-vacancy ratio and the PKA energy. For the same PKA energy, the size of helium-vacancy clusters increases with the He/V ratio, but for the same ratio, the cluster size changes more significantly with increasing PKA energy. It has been observed that the He-vacancy clusters can be dissolved when the He/V ratio less than 1, but they are able to re-nucleate during the thermal spike phase, forming small He-V nuclei. When the He/V ratio is larger than 1, the He-V clusters can absorb a number of vacancies produced by displacement cascades, forming larger He-V clusters. These results are discussed in terms of PKA energy, helium-to-vacancy ratio, number of vacancies produced by cascades, and mobility of helium atoms.

Yang, Li; Zu, Xiaotao T.; Xiao, H. Y.; Gao, Fei; Heinisch, Howard L.; Kurtz, Richard J.; Wang, Zhiguo; Liu, K. Z.



Television and Schooling: Displacement and Distraction Hypotheses.  

ERIC Educational Resources Information Center

|Research on two hypotheses regarding television's possible negative effect on children's academic achievement is reviewed. A lack of support is found for the displacement hypothesis (time spent with television is taken away from more academically beneficial activities) and limited support for the distraction hypothesis (exposure to television…

Roberts, Donald F.; And Others



A linear displacement power factor compensator  

Microsoft Academic Search

Nowadays, the consumer of energy has the concern in operating with a value of power factor inside of a value stipulated by the energy concessionaries. It is know that the power factor is related with the displacement power factor and the total harmonic distortion. The present work has as main objective the development and implementation of a linear compensator of

J. V. R. Nunes; R. A. M. Braga; F. B. Libano; S. L. Muller



Character displacement and the origins of diversity.  


In The Origin of Species, Darwin proposed his principle of divergence of character (a process now termed "character displacement") to explain how new species arise and why they differ from each other phenotypically. Darwin maintained that the origin of species and the evolution of differences between them is ultimately caused by divergent selection acting to minimize competitive interactions between initially similar individuals, populations, and species. Here, we examine the empirical support for the various claims that constitute Darwin's principle, specifically that (1) competition promotes divergent trait evolution, (2) the strength of competitively mediated divergent selection increases with increasing phenotypic similarity between competitors, (3) divergence can occur within species, and (4) competitively mediated divergence can trigger speciation. We also explore aspects that Darwin failed to consider. In particular, we describe how (1) divergence can arise from selection acting to lessen reproductive interactions, (2) divergence is fueled by the intersection of character displacement and sexual selection, and (3) phenotypic plasticity may play a key role in promoting character displacement. Generally, character displacement is well supported empirically, and it remains a vital explanation for how new species arise and diversify. PMID:21043778

Pfennig, David W; Pfennig, Karin S



Ecological Character Displacement in Quantitative Genetic Models  

Microsoft Academic Search

We study, both analytically and numerically, models of ecological character displacement for two species that compete for the same set of food sources. These models include quantitative genetics and Lotka–Volterra type competition and are symmetric with respect to the two species. We allow for various shapes of the carrying capacity and the competition function, and we discuss under what general

Barbara Drossel; Alan McKane



Retraining Displaced Workers--Barriers and Facilitators.  

ERIC Educational Resources Information Center

|Although plant closings and layoffs have been happening for a long time, today's recessions, major changes in the structure of the economy, and a tight job market have combined to make plant closings a more serious problem. Workers are faced with unemployment from both traditional labor-displacing changes, such as the increasing use of robotics;…

Wolansky, William D.


40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2013 CFR

...Materials (ASTM) E 29-67. (b) For rotary engines, displacement means the maximum...combustion chamber between two rotor tip seals minus the minimum volume of that combustion chamber between those two rotor seals times three times the number of...



Simulation of random cell displacements in QCA  

Microsoft Academic Search

In this work, we analyze the behaviour of quantum-dot cellular automata (QCA) building blocks in the presence of random cell displacements. The QCA cells are modeled using the coherence vector description and simulations are performed using the QCADesigner tool. We evaluate various fundamental circuit elements, including the wire, the inverter, the majority gate, and the two approaches to wire crossing:

Gabriel Schulhof; Konrad Walus; Graham A. Jullien



Acoustic shear wave displacement measurement using ultrasound  

Microsoft Academic Search

Echo ultrasound can be used to detect and measure acoustic shear waves. Earlier it has been shown that a phase contrast based magnetic resonance imaging technique can be used for cyclic shear wave displacement measurement. Echo ultrasound presents an alternate method for imaging of such shear waves. The ultrasound based method uses the phase of quadrature echo signals to estimate

Vinayak Dutt; Randall R. Kinnick; James F. Greenleaf



Indian Displacement from the Loess Hills  

Microsoft Academic Search

Indian nations have been thoroughly removed from the Loess Hills of the Missouri River valley. That removal, however, does not conform to the typical story of Indian displacement from the forested East or the Great Plains; it was specific to a time and a place and reflected the changing status of Indian sovereignty in the United States. While it was

Dave McDermott



Revisiting Schramm's Radiotown: Media Displacement and Saturation  

Microsoft Academic Search

In 1959 Wilbur Schramm collected data on the media use behavior of children in what he believed was the last remaining town in North America to have radio as its only electronic mass media, and he concluded the primary impact of new media was the displacement of incumbent media. This research returns to Schramm's “Radiotown” for two follow-up studies to

Jay Newell



Fiber-optic couplers as displacement sensors  

NASA Astrophysics Data System (ADS)

We introduce the novel concept of using a fiber-optic coupler as a versatile displacement sensor. Comparatively long fiber-optic couplers, with a coupling region of approximately 10 mm, are manufactured using standard communication SM fiber and placed in a looped-back configuration. The result is a displacement sensor, which is robust and highly sensitive over a wide dynamic range. This displacement sensor resolves 1 - 2 µm over distances of 1 1.5 mm and is characterized by the essential absence of a 'spring constant' plaguing other strain gauge-type sensors. Consequently, it is possible to couple to extremely weak vibrations, such as the skin displacement affected by arterial heart beat pulsations. Used as a wrist-worn heartbeat monitor, the fidelity of the arterial pulse signal has been shown to be so high that it is possible to not only determine heartbeat and breathing rates, but to implement a new single-point blood pressure measurement scheme which does not squeeze the arm. In an application as a floor vibration sensor for the non-intrusive monitoring of independently living elderly, the sensor has been shown to resolve the distinct vibration spectra of different persons and different events.

Baruch, Martin C.; Gerdt, David W.; Adkins, Charles M.



Job Displacement and the Rural Worker.  

ERIC Educational Resources Information Center

|High rates of unemployment in rural areas poses questions as what education can do with the problem. This report examines the effects of rural American economies as they grow away from agriculture and toward dependence on manufacturing and service industries. Using data from the federal Bureau of Labor Statistics' Displaced Worker Survey, the…

Podgursky, Michael



Microsoft Academic Search

The majority of hydraulic systems are controlled using a me- tering valve or the use of variable displacement pumps. Metering valve control is compact and has a high control bandwidth, but it is energy inefficient due to throttling losses. Variable d isplace- ment pumps are far more efficient as the pump only produces the required flow, but comes with the

Michael B. Rannow; Haink C. Tu; Perry Y. Li; Thomas R. Chase



An inexpensive vertical-displacement indentation tester  

Microsoft Academic Search

A displacement transducer is used to follow the vertical movements of an indenter tip, which is forced into the material specimen under a selected dead weight load. Measurement of indentation depth under load and vertical recovery following load removal allows both plastic and elastic characteristics of the material to be evaluated. The equipment gives consistent results, is readily portable, and

P. J. P. White; M. E. Aulton



Test Approach Lighting for Displaced Thresholds.  

National Technical Information Service (NTIS)

The purpose of the project was to determine the extent to which multiple semiflush-mounted in-runway lighting fixtures, both steady-burning and condenser-discharge types, could replace above-ground approach lighting fixtures to obtain an interim displaced...

E. L. Reamer



Displacement-Type He II Heat Switch  

Microsoft Academic Search

The operation of a heat switch is described in which the conducting substance is liquid He II and in which the nonconducting state is achieved by displacing the He II with a poor conductor, e.g., Teflon. The switch is well suited for use in the first stage of a magnetic refrigerator operating with a bath temperature near 1°K. At this

Ferdinand J. Shore



The politics of displacement in multiparty Kenya  

Microsoft Academic Search

Since the transition to multipartyism in the 1990s, internal displacement in Kenya has been part of political strategies to retain or win power. Cycles of aggression and antagonist articulation of ethnic identity of perceived hostile voters have enmeshed grievances over unequal land distribution into political discourses of exclusion. Increased use of hate speech, intimidation and inability to recover from the

Prisca Mbura Kamungi



Investigation into Displacement of Placer Gold Particles  

Microsoft Academic Search

The experimental research in displacement of gold particles in washed-out thickness of sand-gravel layer is conducted. The parameters of ability of gold particles to migrate in pulp flow are determined, and their immersion into loose soil is investigated.

V. E. Filippov; N. G. Eremeeva; E. S. Sleptsova



Stability analysis of miscible displacement processes  

SciTech Connect

This paper presents a linear perturbation analysis of viscosity- and gravity-induced instability in miscible displacement processes. The analysis takes into account the time-dependent behavior of the basic flow solution. It also considers the velocity dependence in the hydrodynamic dispersion expressions. By solving analytically the perturbation equations, the necessary and sufficient conditions for instability in miscible displacement processes are derived. These criteria are related to the well-known Dumore's velocity and to a critical wavelength for finger growth. Furthermore, they are calculated at the most unstable location in the solvent-oil mixing zone. The equations derived then relate quantitatively major process variables to the onset of instability in a miscible displacement process. Examples are presented to illustrate the applications of the criteria derived. It is shown that as the displacement process proceeds, the injection rate can be gradually increased. Furthermore, for dipping and stratified reservoirs, and for laboratory core experiments, a threshold time can be reached, after which the process is said to be in a state of unconditional stability.

Lee, S.T.; Culham, W.E.; Gary, K.M.



Maximizing Displacement: Mass, Volume and Density  

NSDL National Science Digital Library

This is an indoor lab that uses a boat simulation to demonstrate the concepts of mass, volume and density, and their relationship to displacement. It is a problem solving activity that encourages student creativity resulting in a variety of valid solutions.


A wavelength encoded rotary displacement sensor  

Microsoft Academic Search

A novel concept for a digital rotary displacement sensor is presented. Broadband light issuing from the encoder input fibre is focused on a 9 bit Gray coded dis. Rays emerging from the disc under Littrow conditions are diffracted back to the input fibre by a grating. The output spectrum is encoded as a function of the disc's angular position. The

M. Maghoo; J. Marcou



A wavelength encoded rotary displacement fibre sensor  

Microsoft Academic Search

An improved design for a fibre optic rotary encoder is described in which a Gray code disc is used to encode angular displacement information on a broadband spectrum. Broadband light from a halogen lamp is brought to the encoder by an input fibre positioned in the focal plane of an aspheric lens. A diffraction grating disperses the collimated beam of

M. Maghoo



NDCX-II accelerator, random displacements  


The Neutralized Drift Compression Experiment-II (NDCX-II) accelerator is designed to deposit a pulse of ions almost all at once on a foil target in order to create warm dense matter. This visualization shows the progress of an ion beam through NDCX-II if the accelerating coils are randomly displaced by two millimeters.


DENSE: Displacement Encoding with Stimulated Echoes in Cardiac Functional MRI  

Microsoft Academic Search

Displacement encoding with stimulated echoes (DENSE) was developed for high-resolution myocardial displacement mapping. Pixel phase is modulated by myocardial displacement and data spatial resolution is limited only by pixel size. 2D displacement vector maps were generated for the systolic action in canines with 0.94 × 1.9 mm nominal in-plane resolution and 2.3 mm\\/? displacement encoding. A radial strain of 0.208

Anthony H. Aletras; Shujun Ding; Robert S. Balaban; Han Wen



Nerve growth factor promotes regeneration of sensory axons into adult rat spinal cord.  


Injured adult mammalian axons are unable to regenerate spontaneously in the central nervous tissue. This study investigated in two adult rat models the effects of nerve growth factor (NGF) on the capacity of central primary sensory axons to regenerate back into the spinal cord. Sensory fibers were conditioned by transection of the peripheral nerve 1 week prior to the experiment and identified by anterograde tracing with cholera toxin B subunit injected in the sciatic nerve. In the first model, a predegenerated autologous peripheral nerve graft was implanted as a bridge for the transected sensory fibers into a resection gap in the dorsal columns at the tenth thoracic (T10) spinal cord segment. Vehicle or vehicle with purified mouse or recombinant human NGF was continuously infused for 2 weeks directly into the dorsal column at T9, 3 mm from the rostral border of the nerve graft. With vehicle infusion many ascending sensory axons had grown across the nerve bridge, but essentially none had grown back into the rostral cord. In sharp contrast, NGF promoted the reentry into the denervated dorsal columns of 51% of the sensory axons that had reached the rostral level of the nerve graft. Twenty-six percent had grown 2 mm into the spinal tissue and 10% had reached the NGF-infusion site at 3 mm from the nerve graft. A few fibers were found circling around, but not beyond, the infusion site, perhaps due to the chemoattractant action of NGF. In a second model, the fourth lumbar (L4) dorsal root was crushed 2 mm from its insertion point into the spinal cord and the dorsal roots L2, L3, L5, and L6 were transected. Vehicle or vehicle with purified mouse NGF was infused for 2 weeks directly into the lumbar spinal cord, 2.5 mm rostral to the transition zone of the crushed L4 root. With vehicle, only 6% of the regenerating fibers at the transition zone had crossed the root-spinal cord barrier, but not farther than 0.5 mm into the spinal tissue. With NGF, 18% of the fibers at the transition zone were found at 0.5 mm, 9% at 1.5 mm, and 5% at 2.5 mm (the infusion site) from the transition zone. The present results demonstrate that NGF can promote the regeneration of adult sensory fibers into the otherwise nonpermissive spinal cord white matter. PMID:8690064

Oudega, M; Hagg, T



Inhalational exposure to nerve agents.  


The respiratory system plays a major role in the pathogenesis of nerve agent toxicity. It is the major route of entry and absorption of nerve agent vapor, and respiratory failure is the most common cause of death follow-ing exposure. Respiratory symptoms are mediated by chemical irritation,muscarinic and nicotinic receptor overstimulation, and central nervous system effects. Recent attacks have demonstrated that most patients with an isolat